You can get antihistamine and pseudoephedrine combination pills over the counter. (Product name: Actifed tablets. etc) Its price will be within $5 for 10 tablets.
This medicine is used for nasal congestion and runny nose and may cause drowsiness and dry mouth.
Can single ingredient pseudoephedrine be obtained as an OTC drug?
In Korea, all medications containing pseudoephedrine single-ingredient medicines have now been converted to prescription drugs, so you will not be able to obtain the medication without a prescription.