Tickets are priced at RM89.95+ for a one way trip, and an all-inclusive two-way tickets will set you aback at RM344.90. No comparison head to head with other airlines, as neither Air Asia nor MAS operates on the Ipoh route.
But given the mere 1 hour plus ride, and safety profile, you'd probably be saying your prayers now, after countless joyrides/nightmare-ish experiences on midnight bus rides, about 5-6 hours give or take (read : depending on the hellacious/angelic driver on board!). There are a few bus companies serving the Ipoh-Singapore route, from Sri Maju to Grasslands and such, and tickets are priced at RM50+. (It's been some time since I've been to Singapore, so please pardon the outdated information)
HONG KEE EGG TARTS @ JLN COCKMAN aka JLN DATO ONN JAAFAR