Help with pricing - Sports Photographs

I switched my Smugmug site to a Pro acount about 1 1/2 months ago and have started selling a few photos (right now focus is on cyclocross races).

I have been getting alot of request for photos to link to team blogs which I have been offering for free as long as I get a mention and a link back to my site - right now I am mainly trying to get my name and photos out there - publicity sort of thing to get the ball rolling. $$ are always nice, but I know building a business and becoming a good photographer will take time.

Now I am starting to get some request for my photos to be included in product catalogs - and I really have no idea what I should be charging. These are national companies that sponsor a lot of professional cycling athletes. I have no idea of the brochure (print) circulation - should I ask what the circulation is?

I originally put pricing on my commercial downloads as follows, not thinking I would actually sell any commercial stuff right off the bat - I got these prices just from looking at other SM sites. Should I just stick with these prices - or am I giving the farm away????
LR - $25
HR - $50
Original - $75


I have been using this link for some assistance. http://photographersindex.com/stockprice.htm

I really don't want to loose these first few chances for publication so I would rather price on the low side right now just to get some work published. Any thoughts, suggestions, ways to go about setting a price and not loosing the opportunity??

Thanks,
Michael