Stock inventory and invoicing app (web based preff.)

Hello all, just wanted to check with you all here, a friend of mine is trying his luck with Woolen clothing wholesale business, and he needs to track his inventory inflow/outflow of stock, as well as issue invoices to his customers. Any good apps/software you guyz use ? should be simple, easy to start and use. I'd prefer if it is web-based and in PHP.

Thanks alot...

http://ift.tt/1dvHQ0Z