Not really familiar with Doge, so someone else will have to help. Best to think of BTC not as each individual BTC, but as Satoshis, or SATs. When you get rid of the decimal, it makes everything easier. So 1btc = 100mil SATs. Since 1usd is 2200 SATs at the moment, you just do some basic math.

Hopefully you find someone knowledgeable about Doge. Good luck in your transaction

What crypto are you trying to pay in? If BTC, probably cashapp or strike (if available in your country) is probably the most straightforward. Be forewarned: both of these are KYC (know your customer) apps, so if you are purchasing anything that could be nefarious or illegal, you WILL get caught. BTC is very traceable unless you go through WAY more hoops and steps.

If you are looking for anonymous transactions and trust the seller, sending cash is probably the most anonymous without a ton of steps.