How can I transfer USDT cheaply?

I'm curious about how I can transfer USDT in a cost-effective manner. Are there any specific platforms or methods that you recommend? I've heard about using decentralized exchanges, but are they really cheaper than centralized ones? Also, does the amount of USDT I'm transferring affect the cost? Is there a certain threshold where the transfer fees start to drop? I'd appreciate any insights you could share on this matter.