Being able to hold the mouse button instead of clicking repeatedly would have been very helpful. I found a shop, but never managed to make even 100g, so I didn't see a way to pay the high prices that creepy dude was asking.
Thanks for playing, chests are a very important part of the game, you can find chests around the map commonly and they will provide you with the high prices the merchant asks for. The most amount of G you can find in a chest is 10,000. Not sure how you didn't find one