seems years ago i was on bushmasters mailing list and they sent me a few catalogs after i bought that m17s or XM15 back in the 90s somewhere.
the catalog i am looking at is from 1998.
some interesting prices straight from bushmaster--
bushmaster xm-15 lower stripped--$109.99
bushmaster xm15 lower assembled with a2 stock set --- SALE $209.99
lower parts kit $59.99
m4 barrel assembly $214
xm-15e2 kit $595 complete minus lower
m4, a2,complete upper $485
flat-top stripped upper rec $119
m16/ar-15 blot carrier group BCG $109.99
assembled ar-15/m16 bolt $44
firing pin $5.95
my favorite! hell why didn't i buy this??--LOL 37mm flare launcher kit $199!
40rd mag $24.99
30rd mag $29.99 civilian leo $9.99
aside from the BCG prices of today and some of the other scarce parts--the prices ain't that much higher today.
and you got to consider a 1998 dollar was worth quite a bit more than a deflated 2013 "obamma" dollar.