Given a travel related situation, and given a specific question about the situation, summarize the question into a title

I don't cross the Canadian border by vehicle to the USA very often, and I'm not sure if it will pose a problem that I am crossing for an appointment with a tattoo artist in the morning, returning back later that same day after getting my tattoo.

I would have some US cash with me, and would spend most of it by credit card. I would be spending upwards of $1,000, but not in goods and wouldn't be bringing any goods back.

Does anyone foresee any reason why there may be a problem with spending less than 24 hours there? Are there any rules on how much you can spend in that time period?

Crossing US/Canada Border for less than 24 hours