Agreed! The world of POS and other small business database software is HUGE. The last non-coding job I had was working in retail and the boss had just laid down something like $25,000 for the worst point of sale system conceivable. Most of that was support, training, and installation.
That highlights a big issue, though - anything in that market will necessarily be a very high-touch sales process and therefore very expensive, unless it's absurdly easy to use and install. If you can solve that issue (Square seems to be having a crack at it), you'll probably be extremely successful.
