$1 is far too low to discourage abuse. Spammers and scammers will still make exponential returns. PR agencies are paid tens of thousands to craft narratives for their clients. With institutional actors the sky is the limit. Even just your average basement dwelling troll might consider it worth their while to pay a dollar for a sock puppet account.

Requiring a valid payment method before posting will take out 99.9% of spammers and trolls. Newspapers discovered this when they went behind paywalls. SomethingAwful discovered this 20 years ago when they required $10 to create an account.