You'll have to let us know how that holds up over time, just out of curiosity on my part. I've never tried the spray can bedliner but I have done several Raptor Liner jobs and have been very happy with that.
As for your carpet question: I take used carpet to the car wash and use their hot soapy water followed by the normal cold water rinse. That's as good as anything I've found and way easier than trying to do it at home. For stains it kind of depends - pretty hard to beat laundry detergent for most stains... dilute it with water and work it in with a brush, suck it out with a carpet shampoo machine. Oil & grease can be removed with Simple Green, dish soap, chlorinated brake cleaner. Iron-Out works pretty well for rust stains. Sometimes they are just stubborn and won't come out but I have cleaned some really nasty carpets this way and they almost always come out good enough.
The roof & hood paint: $800 seems like a very fair price for a body shop to paint those. I see at least a day worth of work there. I'd be shocked if most body shops charge less than $100/hour these days. You can definitely do it yourself for a lot less but you'll have time and materials into it - if you use professional products, guessing $2-300 worth of paint, primers, sealer, some other chemicals plus sand paper, masking materials, etc. I think you could make it look OK with Rustoleum type paint but the color will for sure not match... black accents/stripes/etc or something might make it a lot less obvious. That said if it's an otherwise nice truck, do it the right way.
I’ll say it again, in all seriousness, don’t rule out rustoleum. It’s about 10 or $12 a quart, which is enough to paint the whole truck.
As regards color, you could go to Home Depot and find a house paint chip the color of your truck. I remember Gliden put out 1100 shades of white. When you find the right color sample, ask the guy behind the counter what they put in a gallon of white to get it that particular shade of white. Remember a quart will take 1/4 of that amount. Then you could buy some of the small cans of rustoleum, still about five or six bucks, and experiment a little bit and probably get pretty close. Do it in a tuna fish can till you get it right so you don’t waste the whole quart.
Sand the roof and the hood with a palm sander, 120 and ending up with 220 or so. Use the gray metal primer from rustoleum. Put on a couple coats and sand it again with 220.
Pick a cool day in the shade. Mix the rustoleum 4-1 with paint thinner or mineral spirits. That will help it flow when you put it on the truck. Use a 4 inch foam roller, and have a piece of cardboard or whatever and roll it a couple times before you actually roll the truck. That’s so you get an even coat and it doesn’t puddle at the edges of the roller. Put on a couple coats, hand sand that with a 1000 or finer, put on the final coat, sand it again, and then buffet.
Note the rest oleum takes hours and hours to cure. You can put on the two coats of the same color a couple hours apart, but you don’t want to send it probably for 24 hours, so it won’t take a lot of time, but it may take a few days considering the paint curing.
You’ll be under $100 and it’ll look 1000% better.
& BTW, if you screw it up, you can just sand it off. You could leave it on there for a year or two till you get the budget, and then do it at a body shop. It’ll look pretty good in the meantime, compared to what it looks like now.
Just my silly way of doing things…