Just an opinion i think add Altcoin like ethereum litecoin or usdt can be choice to buy copper membership and donation since bitcoin have high fee right now
~Snipped~If you don't wanna pay $5-$10 in fees you could wait for the weekend and make the purchase then.
~Snipped~
In addition to Evilish's comment, you can always purchase with a low fee [if TX fees are high]. No need to wait since there's no time window when it comes to counting such payments as valid here + you can always accelerate those TXs with some of the pools that offer such services for free [ViaBTC and Antpool].
- There's also this:
I doubt anyone would ever donate 10 BTC these days 
Thankfully, this forum no longer needs any sort of donation [self-sufficient].