I kinda feel I need to explain my logic better, because the more I test it the more problems i am facing :(

My Product has the following product Family values:

• Bundle
• Software
• hardware
• Accessories

Then I have a custom object called Bundle_Line_Item__c where I am adding only when I am picking Bundle from the product family. This way I need to update the price of the bundle all the time and for that I am having a trigger to do that which works fine. 

I have couple of scenarios that I need to take care of:

1. when i am creating a software or hardware i want the bundle price to be default 0. I am managing that inside the field. (fixed)
2. when i am picking up product family to be software/hardware/accessories and that default bundle price to be 0 i don't want the standard price to be updated with the bundle price 0. Instead i want to be updated with software price/hardware price/accessories price accordingly. (kinda fixed)
3. Only when I pick Bundle and I have a Bundle Price the price to be updated. (fixed)
4. If I have accessories/hardware/software i want their fields to be taken care of software price/hardware price/accessories price to update the standard price. (same as second)
5. When I pick software as family and software price i want the standard price to be updated for all currencies, same goes with accessories and hardware, only when i pick bundle as family and bundle price as value i just want the price in the field to update the pricebookentry. (NOT FIXED)
6. Optional: Standard price to update the all pricebooks with the values accordingly. But this is another problem that I am facing and i am having it later on my bucketlist.

Here is what I did with the code so far with monsterloomis update.

trigger UpdateStandardPrices on Product2 (after insert, after update) {

    if (TriggerMonitor.runOnce()) {       

        Id PriceBookId = [SELECT Id From Pricebook2 WHERE IsStandard=TRUE].Id;                                                         
        List<CurrencyType> ActiveCurrencies = [SELECT ISOCode, ConversionRate FROM CurrencyType WHERE IsActive=TRUE];                   
        List<PricebookEntry> updatedPrices = new list<PricebookEntry>();                     
        List<PricebookEntry> newPrices = new List<PricebookEntry>();
        
        // SOQL and DML inside for loops isn't bulk-ready, so you'll want to set up your collections OUTSIDE the for loop
        Map<String,List<PriceBookEntry>> prodToPriceBookEntries = new Map<String,List<PriceBookEntry>>();
        Set<Id> prodIds = Trigger.newMap.keyset();
        for (Product2 p2:[Select Id, (SELECT Id, CurrencyISOCode FROM PriceBookEntries) FROM Product2 WHERE Id IN :prodIds]) {
            prodToPriceBookEntries.put(p2.Id,p2.PriceBookEntries);        
        }        
        
        Integer currencyExists = 0;                 
        
        for( Product2 product : Trigger.new)
        {
            
            List<PricebookEntry> loopList = prodToPriceBookEntries.get(product.Id); // needs null checking
            
            // loop through all your currencies
            for(CurrencyType c : ActiveCurrencies)
            {
                PricebookEntry price = new PricebookEntry();
                currencyExists = 0;
                
                for(PricebookEntry l : loopList)        
                {                                           //Is there already an entry in the currency
                    System.debug('l.CurrencyIsoCode: ' + l.CurrencyIsoCode); // debug or use checkpoints so you know what you're actually getting
                    System.debug('c.IsoCode: ' + c.IsoCode);
                    if(l.CurrencyIsoCode == c.IsoCode) {
                        currencyExists = 1;
                        break; // stop this looping once you know it exists, for efficiency                  
                    }
                }

                if(currencyExists == 0)
                {   
                    //Does not exist in this currency: Insert new StandardPrice
                    if(product.Family == 'Bundle'){
                        System.debug('For product id ' + product.Id + ', the currency does not exist.');
                        price.UnitPrice = product.Bundle_Price__c * c.ConversionRate; 
                        price.Product2Id = product.Id;
                        price.CurrencyISOCode = c.IsoCode; // 
                        price.Pricebook2Id = PriceBookId;
                        price.IsActive = TRUE;
                        newPrices.add(price);
                    }else if(product.Family == 'Software'){
                        System.debug('For product id ' + product.Id + ', the currency does not exist.');
                        price.UnitPrice = product.Software_Price__c * c.ConversionRate; 
                        price.Product2Id = product.Id;
                        price.CurrencyISOCode = c.IsoCode; // 
                        price.Pricebook2Id = PriceBookId;
                        price.IsActive = TRUE;
                        newPrices.add(price);
                    }
                    
                } 
                else
                {                                           //Exist in this currency: Update with new StandardPrice
                    System.debug('For product id ' + product.Id + ', the currency DOES exist.');
                    for(PricebookEntry l : loopList)        
                    {                                       //Loop through to find the unique Id for the PricebookEntry
                        if(l.CurrencyIsoCode == c.IsoCode)
                            price.Id = l.Id;
                    }
                    if(product.Family == 'Bundle'){
                        System.debug('product.Bundle_Price__c * c.ConversionRate: ' + product.Bundle_Price__c * c.ConversionRate);
                        price.UnitPrice = product.Bundle_Price__c * c.ConversionRate;
                        price.IsActive = TRUE;
                        updatedPrices.add(price);
                    }else if(product.Family == 'Software'){
                        System.debug('product.Software_Price__c * c.ConversionRate: ' + product.Software_Price__c * c.ConversionRate);
                        price.UnitPrice = product.Software_Price__c * c.ConversionRate;
                        price.IsActive = TRUE;
                        updatedPrices.add(price);
                    }
                }
            }
        }
        
        System.debug('new prices:' + newPrices);
        System.debug('updated prices:' + updatedPrices);        
        insert newPrices;
        update updatedPrices;
    }
}