As much as you can get after getting "everything else". I have about 500 foot and I use it for everything (The new Kentucky Duct Tape). I think you have plenty as it is. After the "paracord bracelet" craze for teenies ends, I figure the price will come down a bit.
I keep 10 feet of it on my wrist at all times tied into an I.C.E. CORD is what I called THEM also make belts gun slings and a lot out of it for something that weighs so little and can do so much I personally think it's a fantastic thing to keep close
I have been thinking of braiding up a bunch of bracelets/belts/gun slings and seeing if it be worth the time tosale them? I have camo colored 550 plus od green black & some earth brown. The one I made my girl is pink.
It seems to be the new crazzzzze!!!! I brad 100 feet rools into a doughnut sinnet. Like the one on the link below and I have it tied down to the MOLLE on my 5.11 BOB. This style of storage makes for a very quick application if need be. I've done it this way for over 10 years. In Iraq 550 cord was almost as good as ammo! From hanging tarps to get some shade to hand cuffing diaper heads when we were out of zip ties. I never saw anyone get out of 550 cord and try to run! Probally, because someone was usally waiting to put some lead in his diet as well.
My brother has made bracelets, gun slings, key chains, and all kinds of other things with para cord so out while family has it handy I have 2 bracelets and a chocker my dads gun slings are made from it him and my mom both wear bracelets from it. I have no clue how many feet we have between all of us that are prepping togther but its a lot!