I'd also put in a recommendation for the Pentax SMC F 70-210 f/4-5.6
The Pentax-made F series, SMC-coated version is quite a lovely lens.
Only complaint I have is that the aperture isn't that big, but then if you want f/2.8, you would exceed your budget
This lens can be bought used for less than $100, if you are patient enough.
However, if you decide to buy this one, be careful to avoid confusion and buy the right one, because there are a few lookalikes out there:
-There is a non-SMC version of the exact same lens (which looks exactly like the SMC coated one except without the SMC lettering).
-There is also a 70-200 version of the lens
-There is a Quantaray-branded 70-210 lens that looks similar
- There is also an FA series 70-200
All of the above do not perform as well as the SMC F 70-210.