Who gives the best price for old coins?

I'm curious, when it comes to selling my old coins, who exactly should I be looking to for the best price? Are there any reputable dealers or collectors that you would recommend I reach out to? And what factors should I consider when trying to determine the true value of my coins? Is there a certain method or process that I should follow to ensure I'm getting a fair deal? I'd really appreciate any guidance you can provide on this matter.