Ahh you did like me and went searching for the nice eutectic solder huh. I damn nearly fell over when I saw the price - you should try sourcing it in Australia OMG. $80 a 1/2lb roll, I kid you not.
Fortunately I found three rolls of nice fine 63/37 Kester with the no clean flux on ebay for $15. You can imagine how fast I clicked that button! (Oh, the packaging looks like its from the 80’s hhahha…fortunately no sign of corrosion)
I just added another column to the comparison - Techni-Tool is now the winner! Not only do they have solder for less than the other three, but they have a lot of Weller soldering iron tips on sale for less than $3 US…
You may want to add the Curious Inventor store to your list for their small quantity solder offerings. When purchasing something like .031" solder it’s great to buy a pound and be done with it, but I’ve never felt justified in spending ~$40 for .015" or .02" solder when such a small amount goes a long way. The Curious Inventor store (from the video at uCApps and on your Wiki) has .02" solder in 1oz. quantites for about $2.50, and 1oz. of .02" solder will last through pretty much all the SMD chips most Midibox builders will ever use.