What should I do with this patio that won’t cost thousands of dollar

powerwash using bleach first

Start by pressure washing the surface.

Sorry wrong link. Correction: https://www.uglyducklinghouse.com/make-patio-look-new-olympic-rescue-it/

Buy a patio mat. People use them for outside their RV’s. They allow water to pass right through without holding moisture from rain or any other liquids like a regular outdoor carpet would. They are light weight, but thick and sturdy enough to lay nice and flat. They also can be hosed off without taking them up and they come in all sizes. I just bought an 8 1/2 foot by 11 foot mat. I know they come in larger sizes as well. I really like it because it’s pretty and very low maintenance. I used high strength velcro to secure the bottom edges to the patio floor. I Bought my patio mat at The Christmas Tree Shop near me which is a discount store, but I’ve seen them in Lowe’s and I know you can buy them on-line, at big box stores and possibly RV dealerships. Look for a sale at the stores. Also the Velcro was about $30.00 from Lowe’s. This would be an inexpensive and easy way to make your patio surface look beautiful without having to put in a lot of hard work cleaning or resurfacing your patio floor. Plus you could just roll up your mat and store in a garage or even in the corner of your patio during the winter or when you are not planning to use your patio for a while. All you would need then would be some lovely chairs, a small table and some ice cold beverages of you choice. Good luck and I hope you find a suggestion that works for you.

After cleaning (either power washing or using vinegar) you could consider investing in some nice outdoor rugs too.