You didn't give any detail (such as links to the products in question, and Mouser lists
90 different products with those specs).
Perhaps you meant:
United Chemi-Con E36D500LPN103TA67M $11.85/singles and
Vishay Sprague 36DY103F050AB2A $41.58/singlesWhen a company sells millions of products, it's safe to say that many of the pricing decisions are automated or semi-automated. Factors that can influence them include competitors' prices, available stock, estimated demand based on sales history, and manufacturing capacity forecasts. In some cases, a discontinued (NRND) part will have a lower price (to stimulate demand), or a higher price (based on requirements in approved designs).
The electronic distributors also provide different packaging options with different prices, like bulk, full reels, trays, loose, and custom reels. Their outlets in different countries also have regulatory, tax, and logistical issues that vary the prices.
In this case, the main difference is the manufacturers. I would expect that certain customers, like defense contractors, have strict Country Of Origin requirements that limit their choices. So prices are segmented accordingly.