It depends a lot on how old your refrigerator is. Look at it this way: What'll it be worth once it's repaired? If the repair costs are more than the value of the working used refrigerator that you'll have once the repairs are completed, it's not cost effective to repair it.
If, however, the repair cost is less than half the value of the unit, I'd seriously consider having it fixed. Keep in mind that old refrigerators aren't worth a whole lot of money, even if they work.
Finally, if repair people are telling you that you're better off replacing it, they're probably telling the truth. After all, they're talking themselves out of a repair job and that in itself should tell you: 1) That you're dealing with a reputable repairman, and 2) He's probably right: Fixing the unit just does not make good economic sense.