Have you considered a horizontal package like Quickbooks? It has every kind of inventory management that you are likely to need, is reasonably priced and has tons of people already using it, so support/training shouldn't be hard to find.
Inputing new stock as it arrives would be done in the purchase orders portion of the program. This section could also handle returns and rma's if needed.
Recording stock usage might be a hassle, since a new invoice would probably be needed each time something is removed from the storeroom. You might want to use a paper system to streamline that during the day, and have someone enter the invoices during slower times. There may also be a more streamlined "sales" entry system available as a third party product.
Hope it helps!
Peace,
Colt
If it's stupid but it works, it isn't stupid