Between $20 and $50, the range of options opens up considerably: clothing featuring an MMA organisation or fighter, small training accessories, and first collectibles become affordable. This is the most versatile price range for a dedicated fan or someone just starting out in MMA.
At this budget, it’s best to choose something genuinely useful or something they’ll wear regularly rather than a novelty item that will end up forgotten in a drawer. A properly sized piece of clothing or a basic training accessory will generally be more valuable than something purely decorative.