1986 Ram 318 Makes Clicking Noise Won't Start

I bought this van last week. It's an '86 Dodge Ram B150, 318 engine.
I bought the van off of ebay so I wasn't sure what I was in for. When I finally arrived to pick up the van it barely turned over, sounded like the battery was dead, a real slow start then it quickened up. On the way home we stopped for some gas and the battery was dead. I had my trusty battery pack jumper and after 10-15 mins all was well and we continued our 3-hour trek home. The past week it's done the same thing so 3 days ago I bought a walmart battery that was recommended for it(the lower cold cranking amps one), it did the same thing then last night the van wouldn't start at all. I was convinced it was because the cold cranking amps was low so I brought the battery back to walmart and swapped it for their MAXX battery that produced 850 cold/1100 warm cranking amps. I also replaced the spark plugs with new platinum ones. I turned the key and now all I get is a clickety click noise. I have the dog house off and can see the fan turning, but there's nothing, not even a sputter and a stop. I'm thinking it's the starter, what do you all think? Any suggestions starting with the low cost dollar fixes would be very helpful as we're pretty strapped on extra funds right now to fork out too much on the process of elimination.

Check the battery cables and starter wiring for loose or corroded connections. These cables have to support a lot of current to run the starter. If the starter is bad you can sometimes repair it with a new set of brushes or just replace the solenoid. I've even opened up solenoids and cleaned the high current contacts to make them work again. Once I even was able to just tighten the screws holding the field magnet in place to fix a starter. But all this may be getting into too much time spent and you'll just want to get a new or rebuilt starter by that time.

But it starts every time you put a battery in it, or charge it, right?

It's not charging for some reason it seems. Alternator?

most likely it is the battery cables

so diagnose like this

get a jumper cable and get it to go from the positive to the post on the starter
cover the 2nd post on the starter with some plastic

use the other part of the jumper cable to go from the negative on the battery to anywhere on the engine.

ok if it starts now its corroded cable from the battery to the starter obviously

that is the most common thing that would cause this

i mean, your starter is not getting enough juice, its only getting enough right after the charge. that cable is corroded, very common.

if u are still having the problem after trying all the other suggestions, i had the EXACT same problem with my 86 D150. check the starter solenoid which should be mounted on the side of the engine bay. the clicking noise should be originating from there. i replaced mine and its run perfectly fine ever since.