I have an old very basic Toyota Tacoma with a (barely) lockable cap, roll up windows, 4 cylinder, 5 speed, A/C, FM Radio with a cassette deck. Nothing else extra.
I get over 30 mpg on the highway, and haven't put a nickle into it in 18 years except for gas, oil, tires, new batteries, brakes, windshield wipers, and a couple of belts and hoses, all of which I installed myself.
The thing is nearly indestructible, and can carry lots of equipment. It's also got heavy built in floor rings to which things can be padlocked. In any case, theft is not a serious problem here in NJ, an oasis of honesty in a wasteland of corruption.
I noticed that these old Toyotas are popular with Middle East insurgents, and they seem to be doing rather well.
The biggest drawback is the lack of a jump seat. Just a bench seat, so only one passenger, two if they're smallish.
This is not a major problem for me, because most of my old dive buddies are dead. Time's winged chariot and all that.