Im runnin a 93 pickup and it shakes pretty good when braking at higher speeds, what could that be caused by?

Another question is, where can I find a gun rack to fit it, what brands and models are out there?

The shaking is caused by a warped disc or brake drum. It could also be an out of balance wheel too.

As for the gun rack, I suggest a locking box that bolts behind the front seat. Displaying guns out in the open seems to cause windows to break and said guns to go missing.

Yeah, probably a warped rotor, but could be a wheel bearing.

Ill have to give the rotor and wheel bearing a look, thanks.

With the gun rack, i was going to use it when traveling to the range or woods, also how well does a bow fit in there.

How can i check those areas to see which is messed up, should i just take it into a garage, you know how much it would cost to fix? thanks.

Well, the basic wheel bearing check is to jack up one wheel and shake it around. If you feel any slop, then it's a bearing, and/or something in the steering linkage for the front end.

If the steering wheel shakes side to side, then it's most likely something in the front. If not, it could be ether end.

As for the brakes. With the wheel off the ground, spin it by hand and have someone put a little brake pressure off. It helps if the engine if off. If it spins free, then sticks, spins free, then sticks, etc, but is smooth without the brake, then it's a drum or disc issue.

I see you have a 4x4. With the FSM and some hand tools, you can do the work yourself.
The rear drums just pull right off once you remove the wheel. Then you can check, clean and lube the parts. Nothing special is needed next to a torque wrench to tighten the lug nuts down correctly.

The fronts are not as easy for this year. It's a disc brake setup and getting to the pads is easy. If you have to change out the disc, then you have to pull the entire hub. Unlike newer Toyotas, the disc is bolted to the back of the hub. It's a pain to replace, but I feel it gives smoother breaking over the newer lug nut type. It's more detail then I can post here and I do suggest getting the FSM as it has step by step instructions with the torque values you will need.
If you do pull the front hubs, inspect and repack the bearings with grease since you will have them out anyway.