I honestly think this would be a good idea, but as some of them said, am confused as to why it's so needy. I personally think it'd be a tad bit cooler if there was both a /call (asks to teleport to someone) and a /join (asks for someone to teleport to you), as I used to see people donating other people cookies so they could join them when they wanted to play together but the spawn was flooded (on Classic Lava that is, as they only had a /join). I also slightly question the need of this command, but I personally think it'd make it a little more fun for people if they could join their friends while in the round instead of building separately.
As for prices and such, I think it'd be best if it had a slightly high price, and like bram said, a higher price the higher the rank. It shouldn't be something you can buy 3+ of with 120 or something when you're an expert, but it also shouldn't be something that clogs up the money you earn. I'm going with french's suggestion and suggestion the use of one call and one join each round or a 5 minute cooldown between when you use the tps, as it might make it a little unfair if you could teleport an entire group of people to a place one round. This is if they were bought
They could also be free, but it would be Apprentice+ and only one call or (not and) one join per round. If we put prices for them, we could go with this:
Player-Crafter: 35 cookies.
Apprentice-Journeyman: 40-45 cookies.
Expert-Master: 57-65 cookies.
Grandmaster: 70-80 cookies.