Please see my post above, where I recommend that @Alexia Johannes
would be better served using a circular saw with guides to match her immediate needs. I note that a guided circular saw is less fussy about the flatness of boards, and doesn't care at all if the edge is straight.
If Alexia is still planning to buy a table saw, then:
* Alexia should know that table saws are designed to cut boards that have a flat face and a straight edge.
* If the board does not have a straight edge, then Alexia can still cut it on the saw using a "jointer sled" like the one that @BigJim
showed, above. Cutting it with the jointer sled will give her board a straight edge. She can flip the board over and put that new edge against the rip fence to give the other side a parallel straight edge, too.
* If the board does not have a flat face, that's a bigger problem. Alexia can flip it over to see if the other face is flat, but if it isn't, the she must flatten it, otherwise she risks a dangerous kickback.
* To flatten a face, Alexia will need extra tools:
+ She could use a jointer to flatten the face, if the board fits. Most consumer jointers are 6 inches, but a few are 4 inches, and expensive ones are 8 inches.
+ She could also use a planer, but she will need to build a planer sled. Typical planers are 12 inches wide.
+ She could use hand planes like they did in the 1800s. That requires a lot of skill, which comes from a lot of practice. She would also have to know how to maintain the planes and sharpen the blades, another "high skill." I do not think this is practical.
+ Alternative: She could turn the non-flat boards into firewood and use only the flat ones.
* If Alexia gets a table saw, she would want to buy or make proper safety aids - good push blocks (not push sticks) and featherboards.
As I said previously, I still think that a repaired or new circular saw with different guides for rip cuts and crosscuts is the best solution for Alexia's immediate needs
Having said that, you gotta' start somewhere. A table saw is how most woodworkers get their start, and it is the hub of a lifetime full of fun and creativity, making wonderful things from wood that started out as real trees from Nature. Just learn all the safety rules until they are ingrained, and always think about where your hands will be before, during, and after the cut. Good luck and be safe!