We are looking for VEX V5 brain, controller, motors, radio, batteries, chargers, etc. We know there is a back log, we are willing to pay premium prices for parts.
Would you be interested in incomplete kits? e.g. Brain, some motors, a radio but no battery or controller? Sorry 
I know it’s stupid to not have a battery but we didn’t order any extras so we kind of need both of ours
It would be helpful if you named your premium.
Yes we are very interested in anything you can sell us. I will start a private conversation with you to discuss further details.
We are willing to buy V5 products for around a 130% mark up. However, we are willing to negotiate prices.
Also, we are willing to throw in 4 V5 turbo motor cartridges for other V5 parts.
We also have V5 torque cartridges that we can throw in.
How much are you charging for the cartridges?
The premiums would most likely be far more than 130% from anyone crazy enough to sell their V5
You MIGHT be able to get it for like $800-1000(probably not), but nobody will give you their v5 for $520 unless they bought a bunch of kits that they don’t need.
I think 30 - 50% markup is reasonable. That is what I expect people to charge.
Maybe what you expect people who are selling anyway to sell for, but, as others say, the demand is exceeding the supply, allowing for much larger markups. It’s about the most basic level of economics. 