Write some software

Windows Sonstiges oder nicht sicher We sell trading card games. There is the site magickartenmarkt where u can see what we need. [login to view URL] The app shoul be able to make a price on his own, in relation to other sellers. We want to have a specific price structure like 20% on top to the first commercial seller. Also we want prices which don't look strange, which means we want to start with the cheapest of 45 cents, till 5€ we would like to have 5cent jumps of those prices, after that 25cent jumps and at 20€ we want 50cent jumps. When we put the card online we want the app to make the price on it's own. Also we want that the app updates our Wantslist, for example if a card comes to a critical low we want the app to put that in the wants list. On the other side if we order cards and recieve those cards the app should clear those cards from the wants list. It should be cleared if we put those cards online our self. We are not sure what the difference between desktoptool or url. So if u interested please explain it to me. Best regards, ISpielRaumSalzburg