Most places have samples you can buy, but if not, you can order the smallest size available (like a 2x3), which is much easier to return if needed.

I’ve ordered many rugs online and only had one (big one) that didn’t work — I put it on FB Marketplace and it sold within hours.

ETA: I’ve ordered from Rugs Direct several times, Overstock, West Elm, Rugs USA, eSaleRugs, Incredible Rugs, Rugs [dot] com, Etsy … all good experiences.

I use overstock for rug shopping. The site has hundreds or thousands of rugs and is easy to navigate, find what you are looking for. They have many relatively inexpensive rugs, but recently I did find the same rug cheaper on Amazon. Overstock has free shipping, not sure sbout returns.

We bought a rug online from West Elm, this way it'd be easy to return if needed.

We also opened a West Elm CC at the time we bought a sectional and area rug and waited to buy when there was "double rewards" so we basically received 20% store credit for the amount we spent which was really handy. We literally got a Sonos Beam free using the rewards that'd accrued the following month.