You don't need to get the carb from a redmax dealer. It's either a zamz or walbro carb most likely. It will have some numbers etched into the body of the carb. Example is cu1-k43 (or something close to that) is a common zama carb on Echo's. After you have that number it gets cheaper since now you google it or call Jthomas or Jacks Small engines to order the carb. Guessing it would be had for under $50. When your on the phone with them ask them to send a air/fuel filter, some line, and the grommet (if the grommet is actually bad). Guessing total price shipped to you will be under $75 for all the parts needed and it will take you 15 to 30 mins to do the first time.
You could save $25 in that total by buying a carb kit instead of the carb. But in my opinion the time it takes and the odds a rookie gets it right isn't worth trying to save the $25.
Don't get me wrong as I have a great relationship with my dealer but when it comes to small orders/repairs it comes down to is it worth his time to order parts and fix it to make $40. Most of the time it isn't.
The lesson you should take from buying the used trimmer is:
1. If you can't/don't repair it yourself you are not saving money.
2. Buying new is the best route to go on handheld units $600 or less.
Looking for blown Kawi 29HP DFI engine's fd791d, whole thing, intake, throttle body, and electronic's. PM me if you have something you would like to sell.