The KPR112 is pretty common and in my local RS they go for 1.3$. The XPR103 which seems to be rare (I got the last three from the store) is in the old Radioshack packaging with green/gray colors (it even mentions that RS is a Tandy division) and the packaging is kinda longer than the common RS bulbs so dont always rely it will be on the lamp drawers. My XPR's were hanged right next to the official maglite replacement bulbs.
Oh, and my XPR's didnt even showed up on their inventory and they had no pricetag on the hanger so the guy told me "just give me one buck for each"!..
So check, check and recheck the whole store..