As just about anyone will tell you, the very first thing you should do is read the game manual and the FAQ from start to finish.
And once you've done that, read it 2-3 more times (not joking) and refer back to it often. Do this before you start buying players, playing around with the draft or anything else (I made a couple of minor mistakes I'd like do-overs on because I didn't read the manual right away). This was by far the best piece of advice I received when I started.
After you've done that, my 2nd recommendation would be to browse through all the older threads in this forum. You'll probably find that many of your questions have already been asked and answered plus you'll get answers to several questions you haven't yet thought of.
As for bids on players, it's all over the map and can't possibly be answered with any specifics. Read the manual first, check out the transfer wire over several days or even weeks and eventually you'll get a better idea of what a good bargain is for the players you're looking at.