The final hours of Amazon’s Prime Big Deal Days are upon us, and you’ve probably made all the big purchases you were targeting heading into the event. But why not spend the waning hours of October Prime Day by seizing advantage of the deals to upgrade your overall tech setup? Here are a handful of under-$100 tech deals you absolutely, positively don’t want to miss before Amazon’s Big Deal Days ends at midnight Pacific time. SD Hynix Beetle X31 portable SSD: $64.99 (36% off) on Amazon We absolutely adored this pint-sized powerhouse when we reviewed it, gracing it with a sterling 4.5-star rating…