Just an FYI, most of the infrared thermometers (hand-held point and click) that are everywhere today have a large margin for error (+ or - 8 degrees per one of those FDA updates I get at work). Keep an old fashioned mercury thermometer around in case someone shows a fever and learn how to read it.
Same thing goes with automated blood pressure cuffs. Basically, they're good at indicating well people are well, otherwise, you get a general indication that things might be off. Buy a GOOD stethoscope and spignonanometer (aren't y'all impressed I know a $2 word?- otherwise known as a bp cuff). BP cuffs need to be sized to the person being tested. If its too tight when placed on the arm, or is too loose or has too much cuff left hanging, the readings will be off- sometimes, quite a lot. I spend a lot of time at work trying to beat that little bit of info into the heads of the medical assistants. The cuffs come in all sizes, pediatric xs thru tree trunk. Consider these items like firearms- you really do get what you pay for. You might be able to McGyver it, but its your, or someone else's, life. I'll put it this way, my go to stethoscope is a Litmann cardiac model- about $300 when I bought it- and worth every penny.
I'd add quik-clot or celox to PK's list, though in pinch you can use instant potatos in nylon stockings- not nearly as good, but it will hellp staunch a bleed. (My understanding is that's where the idea for celox type clotting agents came from- an expediate field dressing).
As far as medical tape goes, don't go cheap. 3M, for me, is the only way to go. If you can afford to get the transpore (paper), micropore (plastic), and medipore (cloth) types, do so. They aint cheap, but they're some of the best, if not the best, out there.
Also get multiple rolls of vet wrap- it's generally cheaper than Coban, and just as good. Do remember that this can tighten over time, so keep an eye out for swelling distally (downstream) to the bandage and loosen/remove it if noticed.
CHG scrub or providone-iodine (betadine) is also a must have if you need to sterilize a wound site before sitching or mending. Without those you have a really good chance of introducing infections into wound beds.
Nitrile gloves- ones that allow you to have a good tactile response. If you have to stitch, start iv's etc, you'll need that. You can generally tell the quality on medical grade ones by how many are in a box for the price- example 200 pairs for 32.00 vs 50 pair for 26.00- you get what you pay for- even though every one of them is made in China, Vietnam or Malaysia it seems.
One last thought, when you're going to yard/estate sales or flea markets, keep an eye out for walkers and crutches in good shape. Also, potty chairs. You can usually get those really cheaply and believe me, if you need them they are invaluable.