Probably these though the numbers aren't quite right for price, so maybe not.

1) Search Dungeon tiles on Amazon. I like these:

https://www.amazon.com/Dry-Erase-inch-Dungeon-Tiles/dp/B016H0TNFY/ref=sr_1_14?crid=2A5B9RGX7E52P&keywords=dungeon+tiles&qid=1640310255&sprefix=dungeon+tiles%2Caps%2C91&sr=8-14

2) Don't buy minis. Lots of free options. One of the fancier free options:

https://www.reddit.com/r/DnD/comments/5gpodp/oc_free_dd_paper_miniature_resource/

You can print these out and have the kids help you cut them out.

Another cheap option - buy the bags of decorative glass stones from a place like Dollar Tree . https://www.dollartree.com/crafters-square-ocean-blue-glass-accent-gems-14oz-bags/105576?gclid=Cj0KCQiA2ZCOBhDiARIsAMRfv9KtPEHLUpPgCOniyPQN9y2joMjMmiIjEsWcLuIbZ6cXd3vDlm09xOcaAqk-EALw_wcB

Get 3-4 colors. Then you can say things like, "Okay, the green stones have bows, the red ones have swords and these three blue ones appear to be holding wands." Or whatever.

You can search RPG Miniatures Bulk. https://www.amazon.com/Figures-Hex-Sized-Compatible-Pathfinder-Skeletons/dp/B07P74R8BK/ref=sr_1_4?crid=35TVBBKO28WLD&keywords=rpg+miniatures+bulk&qid=1640310588&sprefix=rpg+miniatures+bulk%2Caps%2C78&sr=8-4

I also like this set:

https://www.amazon.com/Piece-Army-Skeleton-Warriors-Ready/dp/B00IDBZPIU/ref=sr_1_13?crid=2CT8V3CTQ55G0&keywords=rpg+miniatures+bulk+skeleton&qid=1640310666&sprefix=rpg+miniatures+bulk+skeleton%2Caps%2C99&sr=8-13

They are all skeletons, but you have some weapon variety which is nice. Plus they are yellow, so if your players buy the regular gray plastic tokens, they will stand out.