I'm 'frugal' (cheap ) and use Camel price check to notify me of discounted prices on Amazon.
Occasionally a real bargain comes along. I've been planning to buy more INETUB BA71TGS Flux Core wire, a quality wire from Italy, and I just paid $11.70 per 2 lb roll. It's my favorite. This is the only 'GS' (vendor's choice of ingredients) flux wire that I trust to be uniform, known quality.
The secret to best price is to wait for discounted items to be listed. "Condition: Used - Very Good - Looks and functions as if it were new. Item may not come in original packaging." This was discounted substantially from the usual retail, presently $15.76. I've had good luck buying this top class of customer return or shelf-worn goods from Amazon. All the welding wire in this Very Good category has been a complete unused roll on an intact spool. In contrast a couple of times I have tried the lowest grade, 'Usable, may be missing the manual or components' with random results. Sometimes chunks missing out of the spool, and in one case the first 20% of the wire missing with the rest a snarled mess. Don't Buy That. Amazon should have discarded it.
The other wire I buy when Inetub isn't available discounted is PGN Flux Core MIG Wire - E71T-11, if this one is discounted. But only T-11 in this case, not GS, because T-11 has a known spec for what it's made from. Lincoln's NR-211 is also T-11 spec. As I noted, I'm cheap, Lincoln gets $23.60 for a 1 lb spool. While my most recent purchase of discounted PGN T-11 was $9.72 for 2 lbs. The PGN T-11 wire seems to weld - and feed - as well as the Inetub but its smokier.
I suspect PGN (or their source) spools these small reels from random sources so their non-spec GS wire could be anything. I avoid their GS.
What are other peoples favorites?