Behringer UT300

I ordered this Behringer tremolo pedal to see what the tremolo effect was like. The sound works best for me if I put it on the "choppy" squarewave mode and set the speed a little higher.
The slower speeds (when using the sinewave sound) sound a little less good in my opinion.

The overall build quality is okay, but a few of the knobs seem a little loose and are hard to turn out of the box (This might change over time, but they probably won't loosen very fast if I don't turn the knobs very much.)

Overall it's great for the very low price, and it works well with guitar as well as with a synthesizer or any other sound inputs as a "sequenced" kind of effect.

If you want to get better build quality and a better overall sound, i would recommend getting a more expensive, higher quality option.
But if you just want to try and give the tremolo effect a go for yourself but you don't want to spend a lot of money, I think this is probably a good and reasonably priced option.