I noticed a very nice item a merchant was selling for 90 science. I have 98... I select "buy" button but I can't buy it. In fact, I can't buy anything from him anymore after buying 1 item. I also can't sell him any more items either. Anyone else having issues with the merchant? I even installed a shop to teleport him to a new location hoping that would help.

Didn't have it personally, but one of my friends got that problem while playing with me in multiplayer. It sucked

Yeah I have the same problem with a merchant, I had to save and quit and continue to solve this issue, I was buying the FUZZi with Dust, and I had around 40-50 free dust and the thing cost 18, but i still couldn't buy it, I could buy other items off the merchant, and anything off another merchant, I just couldn't buy the FUZZi...