Hi Karen,

After reading through your code again, I can see that each line item will only have one PriceBookEntry, and each PriceBookEntry will only have one Product2. This means there is no need for Sets in your "non-bulkified" trigger. So here is a cut at the non-bulkified version:

trigger opplineitemtest on OpportunityLineItem (before insert, before update) {
	for (OpportunityLineItem insertedlineitem : system.Trigger.new)   
	{
		System.debug('INSIDE OPP FOR LOOP!!!'); 

		if (insertedlineitem.PricebookEntryId  != null) {
			PricebookEntry pbe = [SELECT Product2Id           
									from PricebookEntry                            
									where id = :insertedlineitem.PricebookEntryId][0];
			if (pbe.Product2Id != null) {
				Product2 prods = [SELECT ProductCode
								   from Product2
								   where id = :pbes.Product2Id][0];
				System.debug('PROD CODE ' + prods.ProductCode);
				
				if(prods.ProductCode == 'AMS300' || prods.ProductCode == 'AMS305' || prods.ProductCode == 'AMS310-5PK' || prods.ProductCode == 'AMS350-5PK' || prods.ProductCode == 'AMS505' || prods.ProductCode == 'MDS405') {
				   System.debug('BEFORE QTY ' + insertedlineitem.quantity);
				   insertedlineitem.quantity = insertedlineitem.quantity * 5;
				   insertedlineitem.unitprice = insertedlineitem.unitprice / 5;
					System.debug('AFTER QTY ' + insertedlineitem.quantity);
				}
		 
				if(prods.ProductCode == 'AMS300-10PK' || prods.ProductCode == 'AMS305-10PK' || prods.ProductCode == 'AMS600' || prods.ProductCode == 'AMS604' || prods.ProductCode == 'AMS607' || prods.ProductCode == 'AMS612'|| prods.ProductCode == 'AMS700') {
				   insertedlineitem.quantity = insertedlineitem.quantity * 10;
				   insertedlineitem.unitprice = insertedlineitem.unitprice / 10;
				}
				System.debug('77'); 
			}
		}
		system.debug('END OF OPPLINEITEM LOOP');
	}
	system.debug('end!!!!!');
}

And here is a cut at a bulkified version:

trigger BulkifiedOpportunityLineItemTrigger on OpportunityLineItem (before insert, before update) {
	Map<Id, OpportunityLineItem> mapPBEIdToLineItem = new Map<Id, OpportunityLineItem>();
		   
	for (OpportunityLineItem insertedlineitem : system.Trigger.new)   
	{
		if (insertedlineitem.PricebookEntryId  != null) {
			mapPBEIdToLineItem.put(insertedlineitem.PricebookEntryId, insertedlineitem);
		}
	}
	
	if (!mapPBEIdToLineItem.isEmpty()) {
		Set<String> fiveXCodes = new Set<String>();
		fiveXCodes.add('AMS300');
		fiveXCodes.add('AMS305');
		fiveXCodes.add('AMS310-5PK');
		fiveXCodes.add('AMS350-5PK');
		fiveXCodes.add('AMS505');
		fiveXCodes.add('MDS405');
		
		Set<String> tenXCodes = new Set<String>();
		tenXCodes.add('AMS300-10PK');
		tenXCodes.add('AMS305-10PK');
		tenXCodes.add('AMS600');
		tenXCodes.add('AMS604');
		tenXCodes.add('AMS607');
		tenXCodes.add('AMS612');
		tenXCodes.add('AMS700');
	
		Map<Id, PricebookEntry> fiveXEntries = new Map<Id, PricebookEntry>([SELECT Id
												from PricebookEntry                            
												where id = :mapPBEIdToLineItem.keySet()
												and Product2__r.ProductCode in :fiveXCodes]);
												
		Map<Id, PricebookEntry> tenXEntries = new Map<Id, PricebookEntry>([SELECT Id
												from PricebookEntry                            
												where id = :mapPBEIdToLineItem.keySet()
												and Product2__r.ProductCode in :tenXCodes]);
		
		OpportunityLineItem item;
		for (Id pbeid : fiveXEntries.keySet()) {
			if (mapPBEIdToLineItem.containsKey(pbeId)) {
				System.debug('BEFORE QTY ' + item.quantity);
				item = mapPBEIdToLineItem.get(pbeId);
				item.quantity = item.quantity * 5;
				item.unitprice = item.unitprice / 5;
				System.debug('AFTER QTY ' + item.quantity);
			}
		}
		
		for (Id pbeid : tenXEntries.keySet()) {
			if (mapPBEIdToLineItem.containsKey(pbeId)) {
				System.debug('BEFORE QTY ' + item.quantity);
				item = mapPBEIdToLineItem.get(pbeId);
				item.quantity = item.quantity * 10;
				item.unitprice = item.unitprice / 10;
				System.debug('AFTER QTY ' + item.quantity);
			}
		}
	}
	system.debug('end!!!!!');
}

 
One problem still remaining with both of these solutions is that whenever you add new 5x or 10x product codes, you will have to update the trigger. You could get around that by adding an integer field directly on the Product2 object. The field could store the quantity multiplier for that Product2, and that multiplier could be used by the trigger. On the other hand, if you don't anticipate alot of product changes, having the codes hard-coded in the trigger might be fine for now.

Regards,

Mark