Decades ago, I bought two assorted trays of nut, bolts, washers, etc. from a PANO advertiser. One SAE, one Metric. Both automotive hardness grade. Think around $30 each. I've used from both over the years. Living out of town, I don't like making 10-20 miles round trips for an item or two.
A quick search took me here. Prices were a bit shocking, but thought some here might see the need. Bolt grades are important...do some research.
https://www.usboltkits.com/