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The stand alone insole market is pretty big and can be very expensive.
I guess it comes down to what shoes you do buy, what is in them already, and what you need to have to make them work for you.
Most more padded or supportive shoes already have significant rise from toe to heel, but many of the thinner or softer shoes, especially vulc shoes have a way flatter overall feel to them.
Some that come to mind are Last Resort, with a completely flat footbed.
Others like Emerica have the G6 insole which might be the most simple on the market right now, but I can't remember how flat it is from toe to heel.
Ideally you would get shoes that have removeable insoles in them that would work for you as well, or that you could swap out if needed, but a little more info might help with what shoes you have had, what you prefer and what you don't want.
The plain / basic flat no nothing $2 insoles from department stores over whatever is in the shoe might be the simplest option if you just need a little more, which I know works for some people I skate with.
Another guy buys high density rubber foam sheets and cuts out his own, but that can easily end up more expensive overall than the specialty insoles.