Once chroming was a relatively cheap process in back alley businesses but, since the 'elf and safety people got involved, finding chromers is difficult and as such when you do come across one they often have little competition to worry about in regards to negotiating their prices. As suggested, what are you having chromed? We might be able to give you some ballpark figures from our experiences.
Half the problem with buying old Aristos and Jubilees, you can get them really cheap but to rechrome them you end up with something costing you three times as much as you paid for it. As example, a Sega lightup cash tray, for a decent job I wouldn't get much change out of £70 down my way. God knows how much a Jennings would cost for a full rechrome?!?! I guess that is the attraction of buying a Mills Hi Top etc. They seem expensive, however, the only chrome you might have to worry about is the handle and collar.
Malc. P.S. My Sega light up, the local guy told me he took four hours of labour to flatten the pitting on the cash try. That's just one part alone. I reckon I got a good price.