The sink prices aren't bad; it depends on the quality of the sink. Some of them are "tinny" while others (older ones) are really heavy and like tanks. If it's a heavy sink, it's a good deal. If it's a lightweight SS, then no so much. I'd opt for deeper because if you're washing a 30 quart bowl, you want to be able to get it into the sink and to be able to move it around. A new 3 bay, 24" depth with both drain boards is about $750. A used sink may or may not come with a faucet and/or sprayer so that's something to consider. New sinks don't include them, you buy them separately.
I hesitate about used refrigeration, you never know what kind of headache you're buying.
For baking racks, do you mean speed racks? That's not a bad price for them, new they go for about $180-200 for the 20 slot ones but again, if any of the slots are dented/banged so the sheet pans don't fit, it's not much of a bargain. If you can, make sure a pan fits on each set of slides.
The sheet pans prices are just ok; again if they are the heavy kind - straight and level, it's a good price but usually you can find used sheet pans for $5 or less at an auction. New ones (16 gauge) are $12/each; 18 gauge is $10 and sometimes if you buy a dozen you can get a discount. Buy the heaviest ones you can find; they just don't make them like that anymore!