Alternatively, if someone could send me 0.003 of either testnet or signet BTC, it'd be greatly appreciated
Sent you a million sat, so you can have plenty to play with. 
If you need more than that, don't hesitate to drop me a message.
You can buy Bitcoin Testnet too if you are very demanding and greedy to have it but I don't buy it.
AltQuick.com & FreeBitcoins.com - Trade BTC, Testnet, & Altcoins. Affiliates 50%
Testnet coins are worthless. Anyone who sells you a testnet bitcoin is spreading the notion that they have value, and thus cannot be trusted. AltQuick.com & FreeBitcoins.com - Trade BTC, Testnet, & Altcoins. Affiliates 50%
Beyond the services mentioned above, there are in-forum faucets as well:
- [Merit] [Faucet] Hey Bitcoiners! Wanna try out the lightning network?
- [For Developers] n0nce's Bitcoin Testnet Faucet [~10 tBTC].