While no one wants to buy a car that’s underpowered, not everyone can afford to drop big bucks on a mighty powertrain. Perhaps that’s why the issue so often goes overlooked -- especially in the classes of affordable cars, where most people shop.

In shoppers’ defense, it’s easier to compare such factors as seating capacity, cargo room and the number of airbags across cars in a single class because that information is readily available. However, it takes quite a bit of math to determine how much power you’re getting for your money, and whether or not it’s a good deal.

To save you time and the headache, we analyzed the offerings in five popular classes. By dividing each vehicle’s starting price by its base trim’s horsepower rating, we identified the best dollar-per-horsepower bargains -- and even compared them to their respective class-average base horsepower ratings. In many cases, what we find may shock you.

2010 Kia Forte

MSRP: $13,695 - $18,695

Base Horsepower Rating: 156

In terms of horsepower, the 2010 Kia Forte offers the best bang for your buck in the class of affordable small cars. While the average base horsepower rating for the class is 135, the base Forte packs 156. Given its low starting price, that’s just $87.79 per horsepower. Compare that to the 2010 Smart Fortwo, which runs $168.87 per horsepower. Granted, the Forte is no speed demon, but it’s certainly more than adequate for daily commutes. "Bottom line: the Forte EX's powertrain is more than sufficiently spirited for suburban driving and quite capable of drama-free passing maneuvers on two-lane highways," writes The Truth About Cars. Plus, the EPA gives the 2010 Kia Forte a maximum city/highway fuel economy rating of 27/36 mpg (depending on trim and transmission).

2010 Chevrolet Colorado

MSRP: $16,985 - $29,835

Base Horsepower Rating: 185

When it comes to hard work, few vehicles compare to a pickup truck. While the heavy-duty kind is ideal, it’s not always practical or very affordable -- which is why many folks opt for compact pickups instead. Of these, the 2010 Chevrolet Colorado offers the most affordable brawn. Rated at 185 horsepower, the base-model Colorado costs just $91.81 per pony. Compare that to the 2010 Ford Ranger and 2010 Hummer H3T, which run $124.62 and $129.35 per horsepower, respectively. The base Colorado even bests the class average of 178 horsepower by seven ponies. Its power output isn’t particularly vast, but it works just fine for light labor. In fact, Consumer Guide says, "With either transmission, the four-cylinder has adequate power for around town driving." Note: The 2010 GMC Canyon matches the Colorado for dollar per horsepower.

2010 Hyundai Genesis Coupe

MSRP: $22,000 - $31,000

Base Horsepower Rating: 210

When it comes to sports cars, horsepower matters. That’s why the 2010 Hyundai Genesis Coupe is such a great buy. It’s rating of 210 ponies breaks down to $104.76 per horsepower. Meanwhile, the 2010 Mazda MX-5 Miata runs $136.59 per horsepower. Do the math, and it’s clear that the Genesis Coupe is a powerful, smart buy. Its base-model rating falls just short of the 217-horsepower average in the class of affordable sports cars. But exclude the significantly more expensive 2010 Nissan 370Z, and the Genesis Coupe actually surpasses the class average by 22 horsepower. And while the Genesis Coupe may not be as sports-tuned as class rivals, it’s still satisfying to drive. "When the pace quickens, the Hyundai displays modest roll and understeer, but its instinct to stay flat inspires confidence when exploring the limits,” says Motor Trend.

2010 Kia Sedona

MSRP: $22,195 - $28,695

Base Horsepower Rating: 244

Soccer moms looking to kick it up a notch with more power while still staying within the family budget will appreciate the 2010 Kia Sedona minivan. Rated at 244 horsepower, the Sedona bests the minivan class average of 208 horsepower by 36 ponies. At $90.96 per horsepower, it also costs less per pony than any of its class rivals. The 2010 Chrysler Town & Country, for example, only features 175 horsepower and costs $143.86 per horsepower. That doesn’t mean the Sedona is a performance vehicle, but it’s definitely up to the task of doing what most people do with minivans -- hauling kids and getting groceries. New Car Test Drive reports, "We let it run up to 95 once, and it was steady, smooth and quiet...At idle, it's so quiet that we once tried to start it when it was already running." Still, its EPA-estimated city/highway fuel economy rating of 17/23 mpg isn’t remarkable.

2010 Nissan Xterra

MSRP: $22,750 - $30,700

Base Horsepower Rating: 261

SUV drivers need a lot of horsepower, especially those who haul loads of passengers or hockey equipment. Shoppers on a budget will do well with the 2010 Nissan Xterra -- which, at $87.16 per horsepower, costs less per pony than any of its affordable compact SUV competitors. Costing $102.80 per horsepower, the 2010 Dodge Nitro is the next cheapest. The most expensive, however, is the 2010 Mercury Mariner -- costing $137.78 per horsepower. Best of all, the Xterra’s 261-horsepower rating surpasses the class average rating of 180 horsepower by a whopping 81 ponies. And it shows. "The Xterra jumps off the line enthusiastically, with the V6 pulling consistently up to its 6,250-rpm redline,” writes Edmunds.  Still, all that power comes at a price. The base 2WD Nissan Xterra nets a disappointing EPA-estimated city/highway fuel economy rating of 15/21 mpg.