Turn single speed into multi speed!
Technically yes, economically no.

You obviously need to obtain a multi sprocket cassette, rear derailleur, shifter, and cable and housing. Additionally you need:


Singlespeed frames have dropouts designed to provide a mechanism for adjusting chain tension by moving the rear hub, so you would need dropout adapters to fit a rear derailleur.
Single speed frames lack shifter cable bosses, so you have to get bolt on ones.


Those might be difficult to obtain. The real problem is that many other major components would need to be replaced:


You would need a new rear wheel with a hub designed for a multi sprocket cassette.
Derailleur chains are narrower than single speed chains, so you would also need a new chain
Because you have a narrower chain you need to replace the chainrings, which as this price point are integral with the cranks and cannot be swapped out, so you need a new crank.


Basically, you have to replace too many of the bike's original major components to make it worthwhile.