I don't think so. I only think they're more pricey because of popularity. I prefer downloading from a website my brother found on eBay. You pay like two bucks and you can download all the songs you want for free.
1.29 songs only cost more because they happen to be the popular songs. The 1.29 and .99 songs run at the same Bitrate so if both songs were 3:00 long they'll take up the same space. 0.99 songs are the ones that aren't as popular.