You can get a decent one on amazon

VectoTech Rapid 128GB External SSD USB 3.0 Portable Solid State Drive https://www.amazon.com/dp/B01JKMZ70G/ref=cm_sw_r_cp_api_i_zDaECb7WZVD7N

For cheap, space shouldn’t matter too much if you’re just going to put Pubg on it.