Beefmaster semen can be had at prices less than those previously mentioned. The Lasater Ranch has sold semen in the recent past (not sure of the prices now) for $30/straw.
There are also some foundation breeders who sell semen in the $20-$50 price range. One of the better bulls in the breed right now, Lasater 1526, has been collected by Gary Frenzel. Frenzel and the Lasater Ranch are also offering semen on one of the best sons (phenotypically) 1526 has produced, Lasater 4248. I can't speak on 4248's production so far. If put into service as a yearling, he should have some sons and daughters selling and entering production this fall.
To me, it seems that the semen that's priced very high is collected from bulls who the owners believe "could" be the next "best thing." I think the show ring helps run some of the semen prices up.
EC