Custom Fields in Post search

What I needed, I think, could be done using Custom fields. So, you create the custom fields, let’s say Name, Height, Weight, etc. and when you enter some value in them, it shows in the post (like CUSTOMFIELD: VALUE, e.g. but I would like to be able to customise it with different fonts, styles, etc) and a search form that could search with MIN and MAX values: e.g. you have an entry for WEIGHT 50kg. and in the search form, someone selects 46-53kg. so this post must show.
https://agency.rbplugin.com/search/ <- It is done here, but I wouldn’t pay for a $500 script just for the search form.