Each job we log through NAPIT costs about Â£2.50ish
sorry can't remember exact amount as we buy block of credits at a discount up front, & as I haven't been doing much domestic work lately it's a while since I purchased any.
Can't say about NICEIC but NAPIT costs are I believe slightly less, ECA similar through BREC.
As we joined a couple of years ago I think you pay a membership annual fee plus an initial visit charge for your on site assessment, sorry can't be more precise but 'the guv' deals with finances & she's not home 0870 444 1392 will get all you need to know from very helpfull young lady at NAPIT, no obligation, all system operators are similar in cost I think,
Have to say have personal bias away from NIC/ECA although member ....find NAPIT 'nicer people to deal with'