There are many things to understand when purchasing cheap tents.  One of them is the structure and what keeps them together.  Tent Poles are very important parts of a tent that keep it standing and in place.  The entire integrity of the structure can depend on these two things.  You are going to have a lot of options to consider in finding a tent that meets your needs and understanding more about what keeps your tent standing will help you find a tent that will last longer under the conditions you will be using it in.
Tent poles are the framework for your tent.  You attach the body of the tent and all of the the tent material to the poles and this gives your tent its shape.  Picture a new house being built.  The foundation has been poured and the house has been framed.  While no walls have been built yet, it is still easy to get a picture of what this house will look like when it is completed.  The tent poles are like the wood used to frame the house.  Once you put them up you are going to have an idea of the shape and size of the tent.  Tent poles are also what can make putting up tents challenging, especially if the instructions are written well.  Tent poles will either be clipped on or pushed through the little sleeves.  Sometimes getting them through the sleeves can be frustrating.
There are two main types of materials the poles are constructed out of.  The sturdiness of tents depends on the quality of the materials being used and what grade they are.

Fiberglass poles are sometimes bulky and usually what comes with most cheap tents.  They easily bend and break in extremely windy conditions and can be hard to repair when broken because of the ends splitting unevenly.  After this happens the poles have a hard time resuming the original shape they once had, if you manage to fix them at all.   You don’t need to worry if you get fiberglass poles if you know you are camping under mild conditions.  Fiberglass does have the advantage of being pretty light unless you buy a cheap tent with bulky poles!   A lot of the lightweight tents you will find will be made out of fiberglass.  These do sometimes get stuck in the sleeves while setting it up.

Aluminum poles, depending on the grade you get, are the most reliable.  They hold up much better to high winds and extreme weather since it is stronger than the fiberglass.   If these break you can splint the break with a tent repair kit and reuse them again. 
Ultimately if you are a casual camper you want to consider how long you plan on having this tent.  If you want it to last a long time and not worry about how sturdy the poles are going to be aluminum will be the better choice. On the other hand, if you don’t plan on it being a lifetime purchase looking for a tent made with fiberglass poles helps reduce the overall cost of the tent.   Also, remember when you select a tent size that larger tents , like cabin tents, will require more poles and this will keep the tents heavier even if they are made with lightweight poles.  This is something else you will want to consider if you need the tent for a lot of people and can’t drive up to your site.