For the types of measurements generally needed to troubleshoot a 12 v system on a boat I think even the "cheap" meters will do. For industrial use we insist on at least a 20Kohm/volt rating, and that generally puts you into the $200 and up range.
My students buy a Fluke 179, around $300 or so... but lately most of them are finding them cheaper on Ebay and Craigslists.
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)