Speaking as a beginner here...I'd recommend getting one from a nursery or store because you'll probably have to wait quite a while for a bloom if you get one online unless you get one in spike. Buy the biggest one you can afford but look at it carefully to make sure it's healthy. (I know, it's not easy when you're starting out.) Check for yellowing leaves, black or brown spots, etc. It's not too horrible if the roots are sticking out from being pot-bound. You can practice repotting right away in that case. Everyone says get a phalaenopsis, but these are easy to abuse. I do better with cattleyas myself. They love southern exposure. If the plant you end up with is in a dark or clay pot, consider changing to the clear ones that have lots of slits to keep the roots aerated. I love the clear ones because you can see when new roots start to grow and if there are beads of water inside, you know it's not time to water yet. And learn about wooden skewers: if you carefully insert one into your plant roots (try not to sever them), it will help you know when to water. Most orchids need to be almost dry before watering. Good luck!

Beginner here too, I started off with Phalaenopsis and have had great luck with them growing, even the ones I got off the death table at Lowe's I also have Colmanra/Onycidium that grows well in the same light as my Phals,I let them all most dry out before watering them or about ever 5 days.

Bear

Oncidium Twinkle from Trader Joe is pretty easy to grow. tehy had sometimes some pretty good orchids for less than 10 $