Payment by Installment

You can do it 2 ways.

Create an invoice for the full amount of the sale.  This will keep your inventory completely up to date (subtracting the total number of items that were purchases).  When payment comes in, just post it against the open invoice the payment is for. Send out a statement each month to the customer to remind them of what is still due and shows the payment received has been applied.

The second way is to do an estimate for the inventory items that are being purchased.  Open an invoice for the customer/job.  A screen will come up saying there is an estimate for that customer/job, do you want to use that invoice.  Click on yes and select the estimate you want to use.  THen a screen comes up to select how you want the estimate to be (full amount of estimate, % of estimate or different amount or % for each line).  Make your choice.  The problem with this is that if you are invoicing for 25% of the total, only 25% of the amount is removed from your inventory.  Then you invoice them each month until the estimate is billed in full.  I would make up all the bills from the estimate and then go back to the invoices created and change the date of the invoice to when you want to send out the invoice each month.  For example for 25% each invoice I would do this month, next month, the following month, ect.

Hope this helps.