Simple Green vs Purple Power

 You can get a whole roll of that filter material from places like Home Depot inexpensively, volume enough to keep you going for a year or two and probably cheaper than the products you are asking about . Then you just cut a patch from the bulk roll to replace your dirty filter as needed.

If you're venting outdoors you can use a looser weave filter, one that cartches the solids and the fumes are moved outside. That's what I do basically. I built my booth to accept a particular standard size furnace filter then buy the 5 pack economy filters for around $8. I only change that out a couple of times a year.

Keep your mask in a good air tight zip lock bag, like the freezer bags, your filters will last longer. The carbon in those filters is activated by air and have a working life, they don't just catch particles but literally eat the fumes. Once the carbon time frame is used up they stop working for the fumes, though may still catch the solid particles for a bit longer ( though you should be using the outer pre filter). You should smell nothing, if you're smelling fumes you either have a bad seal to your face, a defective exhaust valve or the filters need replacing. It's just how it is budget or no budget, it's the matter of pure fact. Don't like it ? Switch to acrylics and use the N95 3m paper masks. For acrylic. I use the N95 with the exhaust vent in them for acrylic and for wood working, works fine. My respirator is for enamels and general solvent paints. If you use the outer prefilter that gets most of the solids anyway and cheap to replace. The carbon canisters eat the solvent fumes which is the damaging part to humans.

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Neither.  I use SuperClean for stripping paint, from styrene, metal, and resin.

I don't need to use cleaning solutions on the filter material. I have a hose attached to my utility sink and I spray the filter with water. I lay it on the sink and by partially covering the end of the hose with my finger it creates a high-pressure spray. The paint comes off, no problem, and down the drain it goes. You could probably even just put it in a bucket of water and swoosh the material around until clean. It might take a couple of rinse and repeats. I'd hate to use chemicals if you don't have to. 

I suppose it will depend on how close the filter is to your spraying. In my case it is about foot from the AB. By the time the overspray makes it to the filter it is already dry, and the paint doesn't stick, it is captured. You might want to try the water method. It can't hurt it.

I DO use Purple Power for stripping paint though and in that case, with the aid of a funnel, I recycle the solution by dumping it back into the jug. I am working off the same solution for over three years. The stuff works well.

A whole roll of that stuff will take up too much space. One has to realize I'm in apartment and I need to budget for space. 

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It looks like Amazon sells aftermarket replacement filters for $4 each.   Might not be much more than the SG you'd dump each time after cleaning.   

A whole bottle of Simple Green or Purple Power is between 4 and 5 dollars at my local Walmart. How many filter washings can I get out of a bottle? I use my airbrush at a high 35 psi because the AndyX method calls for this. Consequently, my paint booth filter tends to load up fast with enamel. Walmart customer reviews claim the Simple Green is less messy and less harmful to skin. Some claim Purple Power is better. Others claim Simple Green is better. Years ago, Simple Green was used by some auto detailers to degrease engine compartments.