Me and are doing Digimon adopt mystery eggs!
We didn't do exactly same scheme of collab, but here is example with my friend's designs: EXAMPLE
(A and C are still opened there as well!)

Total Random:
Baby 1 or Baby 2................$10
Rookie..................................$20
Champion............................$26
Ultamate..............................$30
Mega.....................................$40

Preference - 1 sketch (Suggest a basic Idea and receive a sketch for approval/minor adjustments)
Baby 1 or Baby 2................$16
Rookie..................................$26
Champion...........................$32
Ultamate.............................$36
Mega...................................$46

Preference - 3 sketches (Suggest a basic Idea with details and receive 3 different sketches to pick from for approval/minor adjustments)
Baby 1 or Baby 2..............$26+
Rookie................................$36+
Champion.........................$42+
Ultamate...........................$46+
Mega..................................$56+

Evolution Lines:
3-in-1 Combo (Baby 1, Baby 2, and a Rookie)......$30
3-in-1 Combo single sketch.....................................$36+
3-in-1 Combo three sketches....................................$46+
Full Line (all levels)....................................................$126
Full Line 3 sketches..................................................$150+

First one who grab - they will get!