It depends what your other equipment is. Some are sturdier than others so if you're hanging a bunch of stuff from the top bars you need to get a tent that can handle the weight.
I have $99 48"x48"x80" Vivosun tent. I've had no issues with it. I hang a 6" inline fan, 6" carbon filter, and sealed hood from the top without any issues. The Vivosun might not have the sturdiest frame but it's strong enough. Plus the price is right. I was satisfied with the 4' x 4' so much I bought another 2' x 4' Vivosun to use as a veg tent. I'm perfectly satisfied with both. They're lightproof, have plenty of vents, and serve their purpose for a decent price. You can pay more but I didn't see any reason to.