Turbo Trainer Advice

Fluid will be slightly quieter but magnetic will let you adjust resistance, which you definitely want if you will be using it SS. Otherwise it's much of a muchness, get what's cheap. Keep in mind they all generally hold the rear wheel by clamping on a skewer, so if your rear wheel uses track nuts it probably won't work.

Budget is as little as possible, as I'd like to make sure I use it before splurging.

I completely understand the logic, but bare in mind that the feel of a cheap turbo can make it a miserable experience. If possible, try to find a fluid trainer second hand.