Will I pay less for my return ticket than I would for two single ones?
If a bus company allows to buy return tickets in one purchase, than it usually cost less than a sum of two, single tickets.
Return ticket is cheaper
If a bus company grants a possibility to buy a return ticket in one transaction, then as a rule it's less expensive than two single tickets in both ways. This also refers to open tickets, which dating may be additionally free of charge. Unfortunately not all bus companies provide return tickets. It is necessary then to buy two single ones in both ways.