What are easy and cheap ways to DIY my patio with concrete?

Pavers can be very inexpensive. Level the ground, lay base of sand, set pavers, fill in with additional sand to level and keep in place. Square pavers are about $1 each + a couple of bags of fine sand.

Try cement pavers...this way should anything like a root system invade the area and crack one you can easily replace....we had thought of doing this in our backyard too cement poured but with so many trees around our area the risk that a root may crack the cement we opted instead to lay pavers butted up together this way should one crack we can pry it out fix the ground under it and replace with a new one..our entire back yard is done this way...supports heavy smokers and patio furniture with no issues

You can rent a concrete mixer by the day and buy a concrete mix in a bag. It's a "just add water" product. Level up with dirt or sand so that you are pouring a 4" pad. Using 2 x 4 boards, frame the area. Mix the concrete and pour into your form. When it is 90% dry, you take a float (hand tool) to smooth the surface. You will have to keep a close watch on it to know when it's ready without waiting too long. If you check youtube for bull float, you can find several videos with helpful tips.

Optional ideas: add color to the concrete mix; when it's almost completely dry, use a bristled broom to add a slight texture to the surface. We did the 2nd idea to our walkway but I'm out of town so no picture but check youtube for broom finish concrete if you thing you might like that.

Selena this may be of interest to you :) I have one of these forms and I will be doing this under my raised deck. Good Luck.

plastic cement forms for paving - Google Search