My lbs wants 5eu to tighten the BB (if i take the cranks off)

The tool (key) costs 16eu.

which way would you go?

buy the tool. it will pay off in the long run.

Get the tool; your friends will thank you.

Make friends with the bike shop, and do it yourself. Worked for me. I have pretty much open shop policy. And now I have an extra job for this summer. (I don't really need the money, but I'm hoping to get keys to the shop so I can fix my bike whenever)

-ray

depends how much money you got and if you'd enjoy doing it yourself. i did, it was money well spent, and i've done it at least 30 times since so it's paid for itself.

just remember to grease the bb threads if they're metal. and that the plastic cups will strip. so get it tight but don't stand on the wrench or anything.

I guess, a tool it is.

Also

How much would a 36 spoke rear wheel build cost (just labor)?

I think $40 in labor is about normal for a good builder.

for the rear wheel i've seen shops charge between $15 and $30.

Hmm. not to bad (i don't think) but then theres the spokes and rims!

Thanks for the heads up.