Hey there,
If to answer the question directly, i.e. "if there could be...", then the answer is definitely YES. Paid members are the same kind of registered members, but only having funds on their virtual balance, or an extra membership flag, which would open them the gate to more wider options comparing to the regular ones.
This task is strictly custom, however. In this world, there are hundreds of payment gateways, and each forum may have its own rule regarding specific membership, so even in theory we can't provide a free solution on it. I already did implementatios for PayPal IPN and Verotel annual subscriptions, so if you may be interested in any of those options, you may use our Contact Form to get with me directly, suggesting the options you would like to introduce on forum, and your budget allowed for it. I may work out, actually, any other payment gateway plugged in to miniBB, I guess almost everything could be embedded, as miniBB provides quite an adjustable non-destructive mechanism for this.
We can't talk about "the best" or "the worst" way in this case, it's up to you as a customer what you would like to work out or skip. For your purpose, there could "the only one" way, actually. | 
