Options for camping supplies in Budapest

I know there's a good bit of info on here about the camping scene and the recommendations to bring tents from home etc, but I was hoping people could give options for camping supplies in Budapest when the ONLY option is purchasing the supplies one/two days before Sziget.

Would anyone be able to recommend stores that will still have tents etc stocked the day before Sziget, and the precise location of where these stores are?

Really appreciate it, because we are very close to buying the shitty tents Sziget are selling if needs be.