We want the user to click a button in Firefox to open a USB-driven cash drawer. The cash-drawer provider we currently use (APG Cash Drawers) has some basic software where you can see some back-end DLL type of code. We are open to switching cash drawers if necessary but my guess is that is not necessary. The cash drawer is not tied to a printer.
The fact that it is a cash drawer should not throw you off if not directly experienced with that particular device. It is a very simple USB device that has one extremely simple function: open.
We currently do have another USB device that is triggered from a browser, so we know it is possible. It is a DYMO label printer that uses UniversalXPConnect in conjunction with Firefox.
The budget requirements that [url removed, login to view] asks for are open to discussion. It's not very realistic to ask what our budget is when we don't know what it will take. We don't necessarily go with the lowest price.