Budget eGPU Setup?

Thunderbolt External GPU setups are getting really popular lately, and hence, prices for adapters are getting a bit more economical. I am looking to purchase a laptop for the upcoming semester, and would like to add some upgradability to it. Could anybody suggest whether I should go for Thunderbolt, or would expresscard/mPCIe work fine? Also, any recommendations for laptops? I'm looking to get a laptop and an adapter for under $1000, preferably. The reason I'm asking this here is because eBay and Amazon are very vague on the specs, and I was hoping to get a voice of experience from fellow redditors. Any input is appreciated!

Some information on the usage: -medium to light gaming, stuff like CSGO, GTA V, etc. -no video rendering, photo editing, or any other intensive tasks