I will design ultra cartoon logo, portrait illustration, avatar

Sure! You can order a sketch at low price, then if you like it and want to color it you can use extras.

Absolutely! There is an option in the extras with the name: commercial use, and you can buy it and you will have all the rights of your designs

Revision is something you mentioned about it in your order, but i could not handle it well, so i will do that revision for free. But sometimes your changes due to redrawing, and for redrawing you need to charge extra

If you have source file you can change everything in your illustration, maybe you want to change colors or fonts, if you had the source file you could have done all of them, and maybe you want to print it in large scale or use in small one so you should have the vector file.