The shipping isn't too bad when you consider what 25 (or more) rats adds up to at $4 ea vs $2 ea plus $30 shipping. (That's $100 vs $80 for the same thing). It really depends what the expo vendors charge and even at shows in the same area for me that can be pretty different. Just worth running the math on it to know you're getting the best deal.
Also, not all rats and vendors are equal. The pictures below are one of the rats I bred vs one of the popular frozen thaw suppliers (can't recall which and I've gotten from a few; both pictured frozen). There are certainly worse quality rats than the "bad" one here, looking at how plump and stocky the build is vs the lanky, lean looking appearance of the other. (Seen a few at expos that were nearly emaciated rats being sold.. poor looking rodents are often fed poorly, amount or quality, which makes them lower nutrition for the snake that eats them later.)
One of mine
Identical weight one from a commercial seller
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