If you only have a limited budget, why should you invest in NFT? Good NFT will have a high price, on the other hand, low-price NFT may end as shit NFT like shit coins in the cryptocurrency. I think it is better too little by little invest in Bitcoin. If it is too small, you may choose top altcoins that will have a higher chance to rise up in the future. At least, it is in the top 10. But, it is also risky. Investing in cryptocurrency is all risk, so it will depend on how you want to take the risk and how able you are.