Learn Polish: To włókno jest syntetyczne, toteż jest bardzo tanie. - This fibre is synthetic, therefore it is very cheap.

Toteż means therefore or consequently. It is much more formal and slightly emphatic compared to więc (so). While dlatego (that is why) is very common, toteż specifically highlights a strict, logical consequence, making it perfect for formal statements, writing, or technical contexts like describing materials.

Can toteż be placed at the end of the sentence, similar to how we can move 'therefore' around in English?

No, toteż functions strictly as a coordinating conjunction here. It must stay exactly where it is: at the beginning of the second clause, directly following the comma, to clearly link the cause to the consequence.

Why does the second part of the sentence say toteż jest instead of toteż ono jest?

Polish frequently drops subject pronouns when the context makes them obvious. Since the first clause already establishes to włókno (this fibre) as the subject, inserting ono (it) into the second clause is unnecessary and would sound unnatural or repetitive to a native speaker.

Why do the adjectives syntetyczne and tanie both end in -e here?

They are describing włókno (fibre), which is a neuter noun. In the nominative case, which is the basic dictionary form used for the subject of a sentence, neuter adjectives take the -e ending. Notice how the demonstrative pronoun to (this) also matches this neuter form.