To get an idea of how much things cost, get Cura (a free software slicer) and some of the free thingaverse files and open them with Cura. It will give you an estimate of how much filament it will take (in grams) and that should give you a ballpark on materials costs.
I did have a problem with heat creep on mine making prints fail. I got a higher end heat break (about $35) and that seems to have resolved it. I wound up buying one on Amazon as a gift to my dad.
You can also change the amount of infill to make the part more durable (I start out with 20%).
I'm currently only using PLA + for my filament. There are other filaments that can be used for more durable parts. The main limit on PLA is that heat of about more that 130°F make the parts fragile in use.
Dave, if you want, I can print something for you for you to check out the durablity of it. Feel free to stop by and see mine in action. Just PM me first.
Edit: Dyson to Shark adapter, 12g. 3.87m of filament. 25% infill. 1% roughly of a 1Kg spool for $20. $0.20 for the part, plus electricity. 2hr 38 min print time.
Want me to print it for you Dave?