The ECF already has excellent web hosting for
The main site: paid for by ECF (WordPress / MySQL)
CoM: paid for by ECF (PHP / MySQL)
ECF Coaching: currently paid for by myself (PHP / MySQL)
New grading database: paid for by ECF (PHP / MySQL)
all with Zen Internet. The use of a common ISP will facilitate integration of the membership database (currently lovely old standalone MS Access (ugh!)
CoM uses a PayPal API to interface the CoM application, the ECF shop and PayPal.
Processing credit card transactions is another step-up the ladder.
There is enough expertise in this place to engineer a solution without recourse to outsourcing.
Commercial charges will be prohibitive (typically £800 - 1000 per working day) I suspect.