Plenty of good places around the Web I'm sure! That's the magic of e-commerce for you- I'm sure Amazon has such collections readily available.
If you can't afford the entire collection, there's also this five-set collection of Goosebumps books. Comes with the original, classic 90s covers too! https://www.amazon.com/Goosebumps-25th-Anniversary-Retro-Set/dp/1338149083/ref=pd_lpo_sbs_14_img_1?_encoding=UTF8&psc=1&refRID=WYNGFT659MYPAWCJZBHX
Yep, three.🙂 You can scroll through the pics and see the tins. 😊
https://www.amazon.com/dp/1338149083/ref=cm_sw_r_apan_glt_fabc_G3AE1SNN5V3DGF17Z7NY
https://www.amazon.com/dp/0545847303/ref=cm_sw_r_apan_glt_fabc_1RE8BTWTNCFRW1FJ9X3T
https://www.amazon.com/dp/1338683926/ref=cm_sw_r_apan_glt_fabc_B02GD55Y78NHCV0PN6ZG
You can still find them on eBay and Amazon. They will be releasing a 2ND edition redo can on October 5th.