You would pay more than that for a used engine, so yes it is a good deal.
Service parts are not a purchase cost, they are a useage cost.
The after market mower parts companies do just about all of the service parts for your mower at about 1/2 the price of Husqvarna parts if money is tight.
Most repair only workshops will carry Stens, Rotary, Oregon or Prime Line parts all of which are as good or exceed OEM specifications.
Then there are the real online suppliers like Parts Direct, Jacks , Parts Tree, etc
Try to avoid lazy shopping like Amazon , E-bay or Craigs, that is where the shysters lurk selling defective parts bought as scrap pretending to be OEM or "fitting".