I want a Toyota Tacoma or Chevy Colorado/GMC Canyon because I don't need a full-size truck, however I'm hitting some snags.

The smaller trucks are either very expensive brand new(or a year or 2 older than new) or they are high mileage at 100k for $15k or higher.

My question/discussion is, is it worth it to get a full size truck solely because I can afford the initial cost but the mpg will hurt me in the long run?

I have a budget of 15k, can go to 20k with absolute max. I'm considering an f150 with a 3.5L or if the options are there a 5.0L. I'm not a fan of dodge interiors and same for Chevy's, however I'm open to having my mind changed.

Buy new-ish with a large payment or buy used with a large fuel bill?