I can’t wrap my head around this whole rent thing.

I only started using solana a few days ago, I’m developing a bot which accepts payments from different users. For that I use the solana rpc.

So a user can join a “list” (by some sort of cmd) and he then gets an address where he can send money to. Each user has his own address, this is to keep track of everything and keep it organized. Now, the problem I had when sending transactions on the devnet is, that these new empty accounts need to have some funds at first so they can accept new funds from the user. As far as I understood this is for the rent.

Transaction results in an account (1) with insufficient funds for rent

But why can’t this rent be taken from the first transaction the user makes to that address? Why does it need funds prior to that? I fixed it by using an airdrop, but since I’m only on the devnet I’m unsure if this will even work on the mainnet.

I’d appreciate some guidance if some of you are experienced with this kind of problem.