I got some non-stainless (welded) tube from Metal Supermarkets locally, extra-thick wall (0.120" instead of 0.065") for $58. The normal wall thickness will be cheaper.
Buying “tube” (not pipe, not conduit) that is 1" O.D. is usually quite accurate except depending on the handling it can be slightly smooshed or bent.
Also this might be interesting to you, although it is definitely not recommended. It’s an advanced build that may have issues down the road since it’s sort of a hack: