Long answer : Bullet proof is a misnomer, everything, even the air, will eventually stop a bullet. You can get a suit with ballistic fiber which will work against small and slow calibers. Keep in mind that the damage a bullet does is more than just perforating your clothing. Body armor has a rating system telling you what kind of rounds it can mitigate, although most rifle rounds require some sort of rigid plate to prevent penetration and also dissipate the impact over a large surface area. A thin, flexible bullet resistant suit or jacket is not going to do either of those things very well.
In the US I’m pretty sure you can just buy them online.
https://www.spartanarmorsystems.com/
Do John wick style bullet proof suits actually exist (and work)?
Short answer : No
Long answer : Bullet proof is a misnomer, everything, even the air, will eventually stop a bullet. You can get a suit with ballistic fiber which will work against small and slow calibers. Keep in mind that the damage a bullet does is more than just perforating your clothing. Body armor has a rating system telling you what kind of rounds it can mitigate, although most rifle rounds require some sort of rigid plate to prevent penetration and also dissipate the impact over a large surface area. A thin, flexible bullet resistant suit or jacket is not going to do either of those things very well.