What a REALTOR® adds is access to the Saskatchewan REALTORS Association's multiple listing service, professional pricing against real sold comparables, and negotiation on your behalf, none of which is legally required but all of which affects the price a home actually achieves.
Commission in Saskatchewan is negotiable, so choosing to sell for sale by owner is usually about avoiding that negotiable fee rather than about legality, since the paperwork and disclosure obligations, plus legal fees of $800 to $1,500, apply to every seller whether or not an agent is involved.
Whether skipping representation actually saves money depends on what it costs you in price and time. Get your hand-reviewed valuation from Joel Dyck.