Paper Wallets The Best Option?

I'm soon going to buy my first 3 cryptos: XRP, XLM, DOGE (I'm not interested in your opinion on my investment, bear with me a little longer).
What I intend to do is: buy the coins on an exchange, transfer them in a cold wallet, waith some month, send them all back on an exchange, sell.

From my reaserch I came to the conclusion that Trezor and Tangem are the best options for the amount (about 500€ in total) that i want to buy.

My problem? The cost 80€ (and they are even the cheapest options? wtf?), it simply seems stupit to me to spend 1/5 of my budget on storage instead of investing it as well...

My solution? Create 3 paper wallet (one for each coin), store the coins in them and when the time comes, empty the wallets on an excange all at once and sell. Since from what I understand, there's no way of keeping a paper wallet safe once you use the private key to send any amount out of it. Luckly, in my case that works out perfecly, since I intend to sell them all at once anyway.

What do you think about my solution? Is it outright stupid? Can it be done better? Are ther any other options that aren't any less safe and don't require me to dump 80€ on a glorified usb stick that I probably wont use again any time soon?

I'm fairly new to this world so any opinion helps.