Reasonable speaker replacement

Keep in mind I dont own any CD's, mp3 stuff. I listen to basically whats on the radio.

When I swapped my interior I took the best looking factory GM speakers I had laying around in. The drivers side dash one works and the passenger side rattled horribly so I cut it. hooked up the left/right ballancer in the trunk wrong too so I dont know if the rears are both good but only one speaker works. Im not an audio person, I just want something I can turn on for background noise.

Right now I have a stock 85 or whatever GM radio in my cutlass. I also have a factory equalizer radio but the clock display went out so as much as I like the little sliders I dont use them anyways and I liked the clock/station display better so thats why I have my non cassette base model radio.

What have people done basically just to replace the stock speakers and get it working? I looked on crutchfield and $100 for replacement 4x10's seems rediculous. Is that actually what low level stuff costs? Spend $200 to just get stuff working again. I dont mind spending money but it seems pointless with a 28 year old head unit.

Anybody done a conservative speaker replacement?

That 4x10 being wierd explains it. I did see on amazon theres a pair for $30 which isnt bad at all. Should be able to get all new ones for $45 and free shipping so im not going to complain there.

Do I need to worry about impedence, resistance or anything like that?

I better stop with speakers on my olds. The speakers on all my cars are blown, probably spend $400 replacing everything.