Need some help with pricing my art!

[Extria]

I'm debating on whether or not to open an art shop

If I do, I have no idea what to price things as, soooo, I've come here for some advice on pricing!

(warning the images are a little big; sorry in advance ; n ; )

Human avatars:

Animal / Paw avatars:

[Extria]

heart

[Extria]

Anyone? xD;