Just a few thoughts:

If you are selling a format that can't be played except via a PC/MP3 player, and that has no artwork or other packaging, I wonder if it is worth selling it physically at all? Could you not make the albums downloadable and sell them online individually at a cheap rate?

Is it really beneficial or attractive to offer all 10 together? It might be a bit overwhelming and in some sense devaluing to the music, and also off putting to anyone that already owns a couple of your CDs!

On the other hand, I do understand that it's good to have something to physically sell at gigs...

Speaking personally, I access a lot of music online or through Spotify, but still buy the odd CD because I can play them on the kitchen stereo or in the car, and it's nice to see a bit of artwork, liner notes and all that stuff that gives you a bit of a feel for where the artist is coming from. I wouldn't buy a USB stick because it has none of those features.

I hope this is constructive :)