Apple Maps says Brandon, Manitoba to London, Ontario is 1,375 miles (2,213 km). What vehicle would you replace your Model 3 with that could do the same trip for less than $250? It seems like the $250 is for the round trip, so call it 2,750 miles total. At $4/gallon of gas, $250 is 62.5 gallons of gasoline. Your replacement vehicle would need to get 44 mpg at highway speed to cost less for that road trip. That's doable, if you are only looking at fuel costs for road trips, but there are many other costs other than fuel.
You could replace it with another EV, but in general, the Model 3 is one of the most efficient EVs that is currently available. In addition, anything you replace it with wouldn't (currently) have access to the Tesla Supercharger network and companies like Electrify America tend to charge even higher prices per kWh at their stations, making the economics of road tripping in a non-Tesla even worse.
I totally agree that prices at the Supercharger stations have gone up dramatically. Back in 2018, electricity at a Supercharger worked out to be less than the local residential electricity rates, while with recent increases, I now generally pay 3x the local residential rates. Even with fairly frequent Supercharger use for roadtrips, and that cost tripling since 2018, it still is a relatively small portion of the total operating cost (depreciation, maintenance, insurance, electricity). I've charged at 80 unique Supercharger locations throughout the US in the last 4 years of ownership.
Since you mention the cheap electricity at home for driving around town, what's you ratio of Supercharger to home charging? I've got 66,000 miles on my 3 and over that time, I've consumed 17,464 kWh at home and 4,089 kWh at Superchargers, so 19% of my total kWh have come from Superchargers.
Also, while per kWh pricing has gone up dramatically, the per minutes pricing that
@densum87 showed is even worse. It used to be that per minute pricing was VERY cheap, especially if you disconnected at about 50% state of charge. That's apparently no longer the case when Tesla switched from 2 tiers to 4 tiers on the per minute pricing.