i have ash ctr low, and voltaic tempest with no uv and a toxic 2 star but only has slime med. I usually go in a party and so far there has been a shiver. I could try to get a ctr med bomb trinket to cover all bombs or like a freeze with med ctr. I'm mostly a swordy with haze bombs except in like arenas but I do have dark ret, unheated rss, and master blast. Was just more curious what people do defense wise since bomber armor was only elemental defense. As I think a bomb would help out in almire last room just wasn't sure whether to go for getting seperate ctr or wear bomber armor and get like hearts or brinks stuff which noone seems to like.
And to SYBRM the bombs start to get much better as their radius increases with higher stars. If you are looking for a support bomb you could get a fire one also you could get the static one from tokens from beating the twins enough times. They will help a little getting the 3star fire will help but 4 star is where it starts to get a big radius. If you are looking for support haze style bombs in the long run I would say ash of agni fire bomb, and then a shiver freeze bomb for vana. Also you need to factor in what kind of enemies you are primarily facing as that can change what bombs you want to get. Not sure if you are looking to become a pure bomber or just get one for arenas, jk etc. But I would probably say the fire vaporizer would help a little.
Under 5000cr is about every piece of equipment at 2*, which ranges anywhere from 1k to 6k cr. You won't be getting much with bombs at that level, alchemers don't obtain ricochets until 3*.
You can't just buy something good to use, you have to upgrade/craft it to make it good.