There’s quite a bit under $100, and even under $50. One factor of the cost is the alcohol content, as higher proof whiskies are taxed higher, based on their percentage of alcohol; one reason cask strength whiskies are more expensive. Some of the more approachable ones would be Auchentoshan, a Lowland, unpeated. Their typical expressions, more easily found, are American Oak, Three Wood, Heartwood, and 12 year. I preferred the American and Heartwood. I believe most are $35 - $50. Glenmorangie is also good and approachable, but many are over $50, but typically under $100.
All Single Malts are good, depending on what you enjoy and can afford. Just like wine, price is not necessarily indicative of quality. To me, the reason I like the single cask, cask strength more is that the flavors are not watered-down and human intervention in the flavor profile is at a minimum. The end result is directly related to what went into the cask, the new make, the cask selection, and its ageing. It is the true expression of Scotch, not some flavor profile created by a Master of Malt.
The best way to discover Scotch is to go to a whisky bar. There you can get flights, or at the bar, often you can nose a bottle. If you have certain flavor notes you enjoy in Bourbon, talk to the bartender about your interest in Scotch Single Malts, and explain your flavor/style preferences. You can then jump from there. I personally enjoy the full range of flavors, from fruity, floral, to heavily peated, both Islay and Highland peat, and various cask finishes, such as x-bourbon or x-sherry, etc.
The main difference between Scotch and Bourbon is that Scotch is 100% malted barley, not a mixed grain. Scotch is also typically aged longer, too. Grain whisky is also produced in Scotland, but it is not Scotch. Typically those use wheat and other grains, and may include barley, but not corn, as is required in Bourbon. Their grain whisky is typically not batch or pot still, but continuous distillation.
The flavor profiles are even more varied than Bourbon, as the rules for Bourbon are much stricter than for Scotch. One being, Bourbon must use new American Oak barrels. Like wine, Scotch has a wide variety of flavors. This comes from the many different types of barrels used, almost all are x-casks of some type of whiskey, usually Bourbon, or wine, such sherry, very rarely new oak. Another difference is the use of peat, or not, while drying the barley during malting.
Blended Scotch is whisky that is made with Scotch from more than one distillery, often from various regions, and typically varying amounts of peat, from little to none, to slightly peated. Single Malts are also blends, but use casks from only one distillery; of course, single cask is from only one cask. In Single Malts, the regions make a difference. Many of the most well-known are either from Speyside (named after the River Spey), and Islay.
There are 5 general areas; Highland and Lowland, are the largest areas. Speyside, actually part of Highland, has the most distilleries. Islay (an island off the west coast) is noted for its peated Scotch. There are two main types of peat used in Islay, Islay peat and Highland peat; each has different nose and taste. Then there is Campbeltown, southwestern peninsula. There are smaller noted areas, such as Island, islands off the Northwest; Orkney Islands, off the North coast, and the Isle of Arran, off the Southwest - only one distillery there, currently, but it is good.