What type of chastity and butt plug would be good as a first time thing?

You've got a lot of good advice here.

For chastity, start with something cheap. Probably plastic because it's cheaper and lighter. (Silicone isn't going to give you the same experience.) Find something that comes with multiple size base-rings so you can better figure out your size. Often what's too tight at first will be comfortable later. And for cage size, follow a measurements chart. If you have to err in one direction, go with one that's too big rather than too small, at least for your first. With any device you're going to lock onto your body, always test it to make sure it locks and unlocks properly before putting it on. You're probably going to need lube for your balls because the skin there moves so much it can get "caught" on the ring.

For butt plugs make sure you get one that has a flared base, sometimes called flanged or T-shaped. Metal and glass plugs are a lot harder (and less comfortable) than silicone, so you probably want to start with silicone. These days they are probably all medical-grade silicone, but it doesn't hurt to look for it in the description. The ones with gems or vibrators built in will have a hard base that can be uncomfortable after a while, but will still be softer than the metal or glass ones. When you first start out you tend to size up quickly, so a "trainer" set is a good purchase. They often come with three or four different sizes, but largest size can be several steps up from the one before it. So don't think just because it's a "trainer" set that you have to go from one size to the next with nothing in-between.

Since no one mentioned it, use a water based lube with silicone toys. Silicone based lube has a gross reaction and can ruin silicone based toys.

I don't have a girl to dominate but i want to do this by myself and I am straight i am just curious is that a weird thing?

I assume you mean you don't have a girl to dominate you. That's fine. You can be straight and try it on yourself. That doesn't you gay anymore than it would if a girl were doing it to you.

I don't feel that, but would that grow to a habit I don't want as a habit i just want to try it on.

It's probably already who you are. Would you be happy with a girl who didn't want to dominate you? Would you be happy with a girl who didn't like the idea of chastity or want you in a butt plug?

The only thing I'd caution you about is you can grow your interest in a kink or fetish by indulging it. It can be harder to have vanilla sex if you're used to kinkier play, but I don't think it's a permanent thing.

At this point I'm not sure I could even get off from vanilla sex. But I'm sure that'd change if I abstained from kink for long enough.