How much should a 1969 Ford mustang cost?

I'm looking to buy a 1969 Ford Mustang, but the prices seem to vary a lot and id like to pay on the lower side, but how low would be too good to be true? If I paid 25k for one could it be in good condition or is it likely that it needs repairs?

It depends on the model and originality. Base option 6cyl nisotchback will be cheaper than a fastback 289/ 302. One that's restored CORRECTLY or one that is partially restored or needs restored.
There were many options. Notch back, fastback, standard, auto, with /without AC. PS PB.
Decide what options you would be happy with and the ones you can live without. Can you do the work if it needs it or do you have to find a mechanic? 25k should buy you a nice one with a 289 302. $10k should buy a base 6cyl Fastback
You're gonna pay more for a rust free east of Mississippi than west of. A good place to look is at little car dealers by military post or on CL in military towns.
Also is there small towns around? How I found mine (in the 80-90) was going to small towns every Sat Sun and driving thru alleys and dead end streets. I found a 66 notch back with pony interior 289, auto and a 71 notch back with a 351 Cleveland and restored both. Lastly, take someone with you that KNOWS MUSTANGS

What are you doing with the car? A daily driver? NO, you do not buy one this old.

$45,000 should get you a decent driver that only takes a grand or two a year in upkeep if you are doing a couple thousand miles a year.

Can go cheaper, but maintenance will quickly make up for it.

25k should get you a very nice v8 coupe or a Fastback project.