For drawing blood at home, you will need needles and syringes, alcohol prep pads, latex nitrile gloves, and tourniquets. The latter three items are very easy to obtain. Needles and syringes are doable, but kind of a pain. Despite being readily available on amazon, I don't really trust any that you can buy there, and especially in cuck state commiefornia most places won't sell them to use without some sort of prescription or a medical license regardless if its a human or veterinary supplier.
25-21g are the most common needle gauges used for routine venipunctures. Going as large as 21g isn't really necessary but I do it anyways just because my girlfriend can handle it and I'm pretty good at sticking her. The most common lengths are 1" and 1.5", I haven't found any need to go longer than 1".
As far as syringes go, I usually don't actually need more than 3ml but I have 10ml laying around. Going larger than 10ml isn't really workable. If you want huge amounts of blood, you need to look into butterfly needles, which I have no experience with yet.
You should almost certainly have someone else teach you how to perform venipunctures before you try poking anyone. If any of your friends are phlebotomists, ask them, failing that your next best bet is a heroin junkie.
The only place I have been able to get to sell me good needles and even decent syringes has been calvetsupply. I bought a pack of 21g 1" terumo UTW needles and have been very happy with them, and when performing my best my girlfriend says they are literally painless even though they are 21g. I also got an assortment of exel syringes from them which I have decided suck real bad because they behave as if they were not pumped at all even when I pump them really hard.
Everything else, I have liked using shopmedvet for. You can get needles and syringes from them too if they don't refuse to ship to your state without a license. If they are accessible to you, try to get needles with a safety system to prevent needlestick injuries. I can't get these easily because I live in cuckstate.