Anyone have experience with Heat Surge heaters? Do they increase the electric costs substantially?

I'm sure that they work. I think you are smart to question just how many "pennies a day" it takes. That will depend on the amount of time you use it and how much your local electric company charges for power.

The big concern with these things is the electric circuitry in your home. These likely fall into the same category as other space heaters. They probably use 1500 watts of power (there will be a nameplate somewhere on it that will tell you.). The average household circuit is 15 amps. This translates to 1875 watts available. If you are using 1500 of it for a space heater, it doesn't leave much for the rest of the stuff on the circuit. These have a bad tendency to overload circuits. If the outlets are old this may even do damage to them as well.

You can run them, you may have to be very careful and watch what else is running at the same time..

I've seen the ads too. Just how much "Amish" is in them? (besides the name)

You should look up "flower pot heater pennies a day". Literally heat for pennies a day with a DIY flower pot heater. Also you should look into pellet heaters - they are MUCH, MUCH less expensive than electric heat. Electric heat is the most expensive of all heating options.

Yes, I have the one advertised by the Amish and it does heat one room very well and doesn't cost much. The brand is Heat Surge.

electric heaters are cheaper if kept on low.

electric throw blankets are nice.

get some flannel shirts and heavier clothes.