Anyone may look at the links at the bottom of the home page to 开云体育 to see a list of costs and benefits.
Briefly, the minimum cost (for a long time - until a few hundred users) is $20/month or $220/year.
See the attachment for a brief list of benefits.
There is a free trial ?period. I should have done that or just paid the $20 until more users and experience accrued.
George W9ZSJ