If you just want private commissions once in a while and you don't care about seeing the game or other subscribers' commissions, then this is the tier for you. $1/month is the minimum amount permitted to be a part of SubscribeStar. They have a tip system, which can be used to pay for commissions. (SubscribeStar does take a pretty big cut, but it's a fair price to pay for doing without PayPal.)
Regarding fees, I think I give a lot for a little, but you may need to be patient. And I will charge a lot less if I am allowed to share the art and it fits into G.I.A.N.T. World at least a little bit!