Best way for manually picked "Related Products"?

11 0 6

I'm currently running a test shop in trial mode with the Supply theme and I'm aiming to go for the "Shopify Basic" plan.

I'm trying to figure out the best simple way to have 4 or 5 manually picked  "related products" staticly displayed on each product page. (Different selection on each product page.)

1.) Without making product pages load slower (which most apps seem to cause).

2.) Without an additional monthly fee, because I just can't afford that on the long run.

Considering these two things, does anyone have recommendations for apps or other solutions?

In what kind of price range would a custom coded solution be?
(Maybe possible by the use of special product tags?)