Super-cheap plastic sci-fi troopers from EM4 miniatures. These guys are £3.99 for five. You can get a whole platoon's worth for less than £20! : r/minipainting
El Cheapo Miniatures for Fantasy PCs | Gnome Stew
9 cheap miniatures games under £50 | Dicebreaker
Stemming the Gray Tide, or getting into Minis on the Cheap – White Metal Games
Mage Knight D&D Miniature Lot x20 - Random DND Mini WizKids Bulk Cheap Asst. THG | eBay