I recently purchased a very inexpensive RF Signal Generator from the Amazon website. Although the price shown here is $40, I paid $29 a couple of weeks ago for it.
For the price, it is probably a worthwhile device to have on your bench. However, I don’t recommend purchasing this unit since for a few dollars more (something on the order of another twenty bucks), considerably more functionality is more possible.
Please take a look at the review that I wrote up below.