Too-low quote
A too-low quote sits far under the other prices you were given for the same car and lane. It is the usual opening of a bait-and-switch story. Ask why it is low before you send any money.
When several companies price the same car on the same lane, the numbers should cluster. One number far below the cluster is the too-low quote. The later story, in complaint after complaint, is a deposit, a delay, and a new price closer to everyone else's original number. Sometimes higher.
What to ask before you pay
Ask whether the price is locked in the contract. Ask for the cancellation terms if no carrier accepts that rate. Ask for the company name and docket now, not after the deposit. If the answers are soft, get two more quotes and throw the outlier out. A low number can also be a real backhaul or a flexible date. The company should be able to say which, in writing.
How it differs from a normal range
Estimates vary. A spread you can explain is not bait. A single text that undercuts every written quote, and that requires a fast deposit, is the pattern to refuse. RideShipper's range is not a dare to find someone cheaper than the bottom of it.