but if thats what it cost him it seems ok.
Yeah, IMO it's got to be about half that at least...
Think about what you paid for a single domain, what it would cost to renew 5 times, privacy? IDK, but add that on, and you can get a fairly good estimate of what it cost them for 5 yrs. Also, look at how long it's registered for, it could be on it's 6th registration if they registered it initially a bit over 5 years ago, and could even be registered quite a way into the future if they did a multiple year registration.
They might be making a bit, but not enough to call it business IMO. If it was £1000 you might have something to yell about, but basically they're getting a nominal 'reserving it for you fee' more than anything else.
Do you need all 3? That's up to you, but personally, I'd probably do it if I had the cash laying around and if not, then I'd wait a bit, because if they've had it for 5 years and you recently got the .com and .net IMO it's probably not going any where, but you never know in this business, so IMO it's better to own it.