I think MMario is referring to the compulsory license mechanism, which allows one to "cover" a song that has been once recorded by buying a compulsory license (often from the Hairy Fox). One can sometimes get a better deal by negotiating with the rightsholders, so the question is whether the time spent negotiating is worth the money, and possibly paperwork time (I heard that sometimes licencees negotiate to make quarterly reports to the HFA rather than monthly reports) that will be saved.
A site devoted to music licensing questions is Kohn on Music Licensing. I haven't examined it in detail, so I don't know how useful it is.
As far as I can make out (remember I am not a lawyer, this post is strictly private opinion, nothing in this post is legal advice, etc. etc.) the current statutory rate is governed by 37 CFR 255.3(j):
"(j) For every phonorecord made and distributed on or after January 1, 2000, the royalty rate payable with respect to each work embodied in the phonorecord shall be either 7.55 cents, or 1.45 cents per minute of playing time or fraction thereof, whichever amount is larger, subject to further adjustment pursuant to paragraphs (k) through (m) of this section."
If I'm reading this right, a CD containing 10 3-minute songs would pay a statutory royalty of 7.55*10 = 75.5 cents at the rate quoted above. A print run of 20 CDs would then cost $15.10 in royalties. A CD with twenty 3-minute songs would require a royalty of 20*7.55 = $1.51 per CD. A CD with ten 6-minute songs would require 1.45*6*10 = 87 cents per CD in royalty.
T.