Learn English – Name for something that is being advertised

In common usage, infrastructure often is used unqualified to refer to good physical conditions in a community (as, for example, "Our town has the infrastructure to support your robot factory!"), although it implies little or nothing about tax, economic, and labor conditions. Of course one can also say "Their infrastructure is awful!"; that is, "good" is not an inherent quality of infrastructure.

Note, infrastructure is "The basic facilities, services and installations needed for the functioning of a community or society."

Regarding linguee.com, their "About" page clearly says, "there is no other technology anywhere else in the world that compares with Linguee", so obviously you should keep using it. :) They also assert that the translations they provide (which, if I understand correctly, are in this case English to German) are human-made (or at least human-moderated). In comparing the English and German, it seems that the connotation you suggested for the German word (i.e. "conditions necessary for a business idea to work out") do not hold up in these translations; for example, "worst imaginable conditions" going to "denkbar schlechten Rahmenbedingungen".

I'm not sure how many people would accept it as an "English" word, but gratis - without reward or consideration. comes to mind.

The more familiar, complimentary is often used the same way. Note that this is an adjective. Actual items are normally named (e.g. - a hotel offers complimentary breakfast), or collectively referred to as complimentary gifts. From the "trader's" side, such things may also be called corporate/promotional/business gifts/products; the recipients are more likely to call them freebies (or goody bags, which can be much more than candies for kids).

Gratis is more likely to be found in legal contexts (where you also find pro bono, used to describe work lawyers do without direct payment).

Complimentary is mostly used in commercial contexts where a trader provides something free, usually complementing (going together with) something else you're paying for. Note the different spelling for complimentary (something nice said or given), which many people get mixed up (that's 420 written instances of "complementary breakfast" written in error).