I was a big AES supporter a few years ago, because the high priced games seemed to be only the Metal Slugs (which could be found in 100 other places) and a handful of rare fighting games. However, it seems that even common AES games are now all selling for $100+.
It was less than 5 years ago I bought my AES stuff and I have over 40 games and a lot of them are really great. I am a big beat-em-up fan, which I why I bought the AES. Other than Sengoku 3 which was too expensive even then, I bought most of my games for reasonable prices. Now games like Robo Army, Mutation Nation, Sengoku 2, and Cyber Lip are selling for absurd prices.
Maybe a AES + 161-in-1 cart? I have been thinking about getting one of those.