Where are people buying BTC and transferring it to a wallet at a low cost?

I have primarily bought altcoins the past 4 years but I want to start DCAing into BTC. I had started in 2021 but then stopped and I’m seeing that’s a mistake.

What would people recommend to buy BTC for cheap transfer over to something like a ledger. I currently don’t have ledger I’ve used cold wallets to hold my alts but I want a hard wallet for my BTC. Or do platforms like ledger let you buy BTC directly on their platform?

I could buy the spot ETF but I want control over my own stuff. I don’t need blackrock using me to manipulate markets.