You're getting good advice so far. My 2 cents..
Do 2 things; the first very easy and the second harder.
First, follow your own tastes. Not mine. Not somebody else. Knives are like shirts. You should like what you have and what I have may not suit you.
Second, avoid junk. Luckily, there ARE knives in the $20 that aren't junk so there's hope. But there is a lot junky $20 knives too, so the trick is avoid junk. Three ways of avoiding junk.
First, use this forum, as you already are. You might also type the following into google site:
www.bladeforums.com budget knives
This will search only stuff from this site. Adjust the search terms if you want. Budget folders might give you more hits.
Knives that get mentioned a lot in threads like this include (but are not limited to): Kabar Dozier Drop Point Hunter, ESEE Zancudo, Ontario Rat and Rat 2, Buck Vantage (big box building supply stores often have them in this range), Opinel (8 or 9), Victorinox SAKs, Case Sodbuster or Sodbuster Jr.
A second approach is to stick to a reliable brand and choose a model you like. CRKT, Kershaw, Cold Steel, Opinel, Victorinox and Case are brands often associated with providing good value at a reasonably low price.
A third approach which will incite the steel police to stagger out of the dark shadows of the forum like some Walking Dead marathon is to buy any knive that you like the looks of that has a blade steel hardened in the 56-58 Rockwell (Rc) range. As you gain experience with knives you may develop a strong preference for different steels but until then, I think its safe to say that if blade is adverstised to have a hardness in the 56-58 Rc range, the manufacturer is doing an acceptable job with their heat treatment, at least in terms of having a usable EDC knife. This advice just swept pages and pages and pages of detailed and heated forum debate under the rug and you may get an interest in that stuff at some point in time.
Good luck