SS2 home cart - $60
Metal Slug MVS - $60
Conversion Labor - $70
So, about $190 for a Metal Slug. You can find the MS and SS2 cart cheaper, I was just using the higher end prices in the example. You canfind SS2s for about $40 and MS for about $45 if you look long and hard enough..
We've also made some home-made inserts and cart stickers (manual coming soon) for Metal Slug since it's the #1 converted cart. These files are free to download, or if you're lucky I may have a set already printed when I do the conversion.