Where do I begin? First, I respectfully disagree with most of the original post. Secondly, there is a huge difference between buying an entry level solid body and an entry level acoustic, but that's for another discussion. My advice is more like this-
1. Go to a huge guitar store, so you can play a lot of guitars, including some you can't afford. The big stores buy in quantity, can sell at a lower price, and will have a larger inventory. There are really 3 types of guitar stores- the huge chains, like Guitar Center, mom and pop stores, which usually sell off-brands and band instruments, and specialty stores, which tend to sell high-end, hand made, and vintage instruments. Mom and pop can't compete in selection and price, and the specialty stores are mostly out of a beginner's price range.
2. Take a good friend with you who really knows guitars, and has similar musical interests. He will help you to ignore the big store's (usually asshole) salesman. He can't tell you why you should buy any given guitar, but he may be able to see things wrong with it that you can't.
3. Buy the guitar *you* like. not the one your buddy likes. You are the one who has to play it, not him. But, try to buy a guitar that your buddy admits is priced fairly, and doesn't have obvious flaws.
4. Here is a point where I *really* disagree with the original post. *Never* buy a guitar you haven't played, Not on line, not one *in the box* where you only played the floor model. Guitars are like snowflakes or fingerprints. They are made out of wood (usually), which is not a uniform substance. The cheaper a guitar is, by and large, the more variable the quality control is. If you play a bunch of supposedly identical guitars, you will find huge differences between them, even in expensive models.
5. The concept of "set up" has been mentioned above. What "set up" is, or isn't, varies a lot between different types of guitars, and may or may not have been done well already. The more setup a guitar requires, the more you have to like it for it to be worth the price.
If a new guitar is badly set up, it often indicates that it was made more by a machine than a human, or a human who didn't care much. Generally, I prefer the work of humans, but not always. Usually, electric guitars with adjustable bridges and truss rods are more adjustable than acoustics, and classical guitars have damned little adjustability built into them. If I think an acoustic is set up badly to begin with, chances are I won't buy it.
6. Before you play an electric plugged in, play it unplugged. You can always modify pickups later, but if the guitar sucks unplugged, amplification will not help. On the other hand, electrics that sound good unplugged usually sound good plugged in.
7. Guitars are like cars. Never pay the sticker price without attempting negotiation. Always offer less than the asking price, and try to get them to throw in accessories, especially a hard case. This is an area where it may be a good idea to shut up and let your guitar buddy do the talking. Make sure thay give you the warranty paperwork and a truss rod wrench that fits, if the guitar has a truss rod.
8. If they are going to do a setup on the guitar, and you have a preference in strings, make sure the type of strings you like are included with the guitar, even if you have to pay for them. String gauge is critical in set up. If you like lights, don't let them set it up with mediums. If the guitar really needs set up, and they charge extra for that, that is where I am likely to take it to a specialty store later and pay the nice real luthier to do it right. No, he probably won't do it for $20, because he actually has a clue and may do something that involves actual work.
9. Inspect every inch of the guitar closely. A new guitar should not have visible damage, and even non-critical wear such as pick guard scratches on a floor model may be a negotiating point on the price. If you do find damage or fit and finish issues, let your guitar buddy tell you if it is functional damage, or just cosmetic.
10. I know it's hard, but try to concentrate on how the guitar feels and sounds, not how it looks. Buying a guitar based on its looks is like buying a car based on the paint job, or marrying a woman because she has good legs. You may live to regret it later.
11. When it all comes together, you will know it. If you are torn whether to buy a guitar or not, don't buy it. Asshole salesmen depend on your emotions being out of control to pressure you into buying a guitar that isn't quite right. When you play the right one, you'll have no doubts. If you find it really hard to put it back on the wall, that's a clue. And don't be afraid to walk out of that store without buying a guitar. The store will most likely still be there tomorrow.
I own a fair number of guitars, some of them higher end, some of them mid priced, and a couple that really were dirt cheap, because you have to have expendable guitars for camping and other risky situations. The cheap ones are some of the ones I'm most proud of. Anyone can buy a good $5000 guitar. It only takes $5000. When you buy a good $80 guitar, you have actually accomplished something. I mostly use a Taylor 710CE for recording, and I assure you, I went through a hell of a lot of acoustics before I found it. On the other hand, you'll often find me on top of a mountain playing my Mitchell MD100S. I bought it brand new at Guitar Center for $80. Marked down from $139 for Memorial Day, I had a 20% off on any one item coupon which went toward that bad boy. Sealed tuners, compensated bridge, ivoroid bound neck and body, purfling and abalone rosette. Solid spruce top, mahogany sides and back, absolutely *perfect* intonation, excellent action. Does it sound like a cheap guitar? You bet. When you buy a more expensive guitar, you get better wood, and that's all....BULL! That's like saying that when you buy a Rolls Royce instead of a Toyota Echo, all you get is better metal. But I'm proud that I found a playable acoustic with perfect intonation for $80. Best of luck to all who seek a cheap guitar, whether it be your first, or as a back up for your Huss and Dalton.-Richie