1994 Ford Ranger Serpentine Belt Squealing and Smoking

The pulley may be out of alignement.
to have it done properly, a shop will do it right, i don't want you be angry because I refere you to someone else. ok :-)
how much it cost? depend where you live, call a shop and ask them how much pulley alignement cost.
But, if you need my help,
what you need to do is to align the pulley and attach the belts.
The pulley alignment may be tricky and require some time to get right. 1) Align the Power Steering pulley to the other pulley assemblies on the vehicle. In the picture, a wood alignment tool is being used. The far end of the alignmnet tool rests on the crankshaft pulley, and the near end is on the power steering pulley. Alignment is made with the power steering pulley puller and press. Adjust the power steering pulley until it is well in line with the crankshaft pulley. NOTE: Two things will likely happen if the pulleys are not in alignment. (1) The belts will wear more rapidly, and (2) belt noise will occur.( that what is happening to you vehicle)
put the belt on last.

The problem may be with pulley alignement or you just need to change your belt.
If the new belt makes noise and get caught after few days, your pulleys are out of alignement.

What you can do is to put a new belt and give a chance. It may solv the problem.
Let me know what happens after you put a new belt.

Here's my two cents:
The pulley you're showing looks like your AC compressor. Chances are it's locked up. A new compressor may run around $300-400 + installation (maybe around $150). I would shop around to find the best deal.
If you're lucky your problem is only the clutch, in which case you can replace it without opening the system (and it's cheaper).
Also, if your car has its original AC system, it may be made for R12 refrigerant. This refrigerant is no longer used, almost impossible to find, and very expensive.
If/when replacing the compressor, you may have to convert the system to R-134A refrigerant.

Hope this helps