Apex:

public class AddNewProducts {

    public List<OpportunityLineItem> oppLI;
    public OpportunityLineItem oli = new OpportunityLineItem();
    public Opportunity opp;
    public String oppName, oppRenewDate, oppCloseDate, pstyle, actMsg, sd;
    public Date ord, ocd;
    public List<Product2> product;
    public PriceBookEntry pbe = new PriceBookEntry();
    public Boolean saveMe;
    public Double awardprob, quant,up, dp;
    public ID pricebookID, opporID; 
   
    //Use the constructor to build a list of related line items
    public AddNewProducts(ApexPages.StandardController controller) {
        Id id = ApexPages.currentPage().getParameters().get('id'); 
       
        oppLI = (id == null) ? new List<OpportunityLineItem>() :
            [SELECT UnitPrice, ServiceDate, Quantity,PricebookEntryId,ListPrice,
                PricebookEntry.Name, PricebookEntry.ProductCode, OpportunityId, Id,
                Award_Probability__c
                FROM OpportunityLineItem WHERE OpportunityId= :id];
               
        opp = (id == null) ? new Opportunity():
            [SELECT Id, Name, Renewal_Contract_Date__c, CloseDate
                FROM Opportunity WHERE Id= :id];
    }//end constructor
   
    public void productSearch()
    {
        actMsg = '';
        if(pstyle != '')
        {
            for(PriceBookEntry pbe:[SELECT Id, UnitPrice, IsActive
                        FROM PriceBookEntry
                         WHERE Pricebook2Id    = '01s800000006gVfAAI'
                         AND Product2.Name =: pstyle])
             {
                
                 if(pbe.IsActive == FALSE){
                        actMsg = 'You cannot add an inactive product.';   
                        saveMe = false;                       
                 }//end if
                 else{
                     actMsg = 'Use the \'Tab\' key to save your product';
                    saveMe = true;
                                                 
                     // add the line item... or not
                    oli.UnitPrice = pbe.UnitPrice; //End User Price
                    oli.PricebookEntryId = pbe.id; //only the standard price book
                    oli.OpportunityId = opp.id;         
                                       
                    dp = oli.UnitPrice; //Dealer Price
                    up = oli.UnitPrice; //End User Price
                    pricebookID = pbe.id;
                 }// end else
            }//end for prod loop
        }//end if
        else{actMsg = 'Please enter a product style to search for.'; saveMe = false; }
        //return null; //end else
    }//end pagereference method
   
    public PageReference save() {
        //we will only save  products to opp line items if product is valid
        if(saveMe == true){
              OpportunityLineItem joint = new OpportunityLineItem();
            //joint.UnitPrice = oli.UnitPrice;
            joint.Quantity = quant;
            joint.TotalPrice = quant*up;
            joint.ServiceDate = Date.valueof(sd);
            joint.Award_Probability__c = awardprob;
            joint.PricebookEntryId = pricebookID;
            joint.OpportunityId = opp.Id;
           
            try{
                   insert (joint);
                   PageReference pageRef = new PageReference('/apex/AddOppLineItems?scontrolCaching=1&id='+opp.Id);
                   pageRef.setRedirect(true);
                   return pageRef;
               }
            catch(DmlException ex){
                ApexPages.addMessages(ex); 
                return null;
               }
        }//end if
        else{
            actMsg = 'Product cannot be saved because its not active or does not have a list price.';
            return null; 
        }//end else 
    }//end method
   
    public PageReference goToProducts(){
        PageReference pageRef = new PageReference('/ui/opportunity/SelectSearch?addTo='+opp.Id+'&retURL=/'+opp.Id);
        pageRef.setRedirect(true);
       
        return pageRef;
    }//end method
   
    public List<OpportunityLineItem> getoppLI() {
       return oppLI;
    }//end method
   
    public List<Product2> getproduct() {
       return product;
    }//end method
   
    public Opportunity getopp(){
        return opp;
    }//end method
   
    public OpportunityLineItem getoli(){
        return oli;
    }//end method
   
    public PriceBookEntry getpbe(){
        return pbe;
    }//end method
   
    public double getuserPrice() {
        //return userPrice;
        return up;
    }//end method
   
    public void setuserPrice(double g) {
        //this.userPrice=g;
        this.up=g;
    }//end method
   
    public double getdipper() {
        return dp;
    }//end method
   
    public void setdipper(double c) {
        this.dp=c;
    }//end method
   
    public String getoppName(){
        oppName = opp.Name;
        return oppName;
    }//end method
   
    public String getoppRenewDate(){
        ord = opp.Renewal_Contract_Date__c;
        oppRenewDate = String.valueOf(ord);
        return oppRenewDate;
    }//end method
   
    public String getoppCloseDate(){
        ocd = opp.CloseDate;
        oppCloseDate = String.valueOf(ocd);
        return oppCloseDate;
    }//end method

    public string getprodStyleNum() {       
        return pstyle;
    }//end method
   
    public string getactMsg() {       
        return actMsg;
    }//end method
   
    public void setprodStyleNum(string s) {       
        this.pstyle=s;   
    }//end method
   
    public double getquantified() {
        return quant;
    }//end method
   
    public void setquantified(double v) {    
        this.quant=v;
    }//end method
   
    public String getserviceD() {
        sd = oppCloseDate;
        return sd;
    }//end method
   
    public void setserviceD(String d) {       
        this.sd=d;   
    }//end method
   
    public double getAward() {
        return awardprob;
    }//end method
   
    public void setAward(double r) {       
        this.awardprob=r;   
    }//end method
   
}//end class