Not really, some stuffs in Mustafa are more expensive than NTUC/Cold Storage, but for home appliances / electronics, most of them are quite resonable
The appliances I bought from Mustaffa were cheaper because I always take my time to do comparison shopping. Nowadays you can never assume that Business XYZ will always have cheaper prices.
There might be other places such as Goh Ah Bee? where you can order all your appliances but you must know the model you want. They'll contact the agent & order the item for you. But Mustaffa's a good place to look see & touch the items.
Mustaffa also has a wider range than NTUC/Cold Storage when it come to appliances & electrical goods.