223.5mm stainless

Has anybody found some stainless 23.5 or 3/4 emt sized stainless for a good price. i have built a 3ft x 4ft with supports for the outer frame but the x and y axis tubes have a slight droop to them in the middle and would like to get something more stiff that will work with existing printed parts. If anybody knows a good source online or another type tube besides EMT that will work in place that would be great.
Thanks in advance.