I would really like to get him a Specialized Hotrock but I'm having a difficult time justifying the $160 for something I know he'll outgrow in one year, two at the most. A "Schwinn" for $70 doesn't look too bad but I realize its not the real thing and pretty much crap compared to a Spec, Giant, Trek, etc.
I feel bad for thinking cheap since I roll around on a Spec road bike and Trek MTB. One advantage I would have over a typical big box bike buyer is that I know to check the assembly and keep an eye on things. Should I save the cash now and make the big spend when he moves to 24 inch in a year or so or just bite the bullet? Better yet, is there a decent trade off in the $100-120 range?
Check to see if you can find a used model, you may be able to get a good deal that way. Craigslist and friends might be able to put you in touch with someone looking to sell a good 20" bike.
It is a tough call on what to do. It does not sound like he has younger siblings that could inherit the bike which makes that bite more palatable. If your son really likes riding then that extra bit will be worth it if the quality is there. Test ride the bikes yourself and see what you think between them. I have a slightly smaller frame but I test ride all my kids bikes from tricycles on up. I am not always happy with what they are but I know what I am getting.
Spring is garage sale time! You may want to check out the thrift stores. I purchased my son's Specialized 20 in (tire size) for $4.99 @ the local Salvation Army, It need some work but is a quality bike that should last through all 3 kids
I did something this weekend I didn't think I would do. I purchased a $150 20" bike for my 7 year old. It was his reward for learning to ride a 2-wheeler and the difference between this bike and the Toys 'R Us one it is replacing is night and day. It's lighter than the 16" one, the wheels are true, the geometry of the frame works really well for him, the clamps for the seat and handlebars are solid, etc. My younger son will be able to use it when the older one outgrows it, and it will probably still have a decent resale value unless they tear it up. I knew it was worth it when we went out to the bike path, he took off, came back grinning ear to ear and yelled "I'm Free!" He then told me that he loves biking even more than I do. I got it at REI and they adjust it before it leaves the store and they do a free service for it too. What the heck, he takes his lunch to school everyday instead of buying it there ($1.70/day) and I have the best kids.
Check in on the Folding forum for more info about this. At least one regular in there justifies his fleet of folding bikes by sharing them around the family. One benefit of many folding bike models is that the seat and handlebars telescope up and down, making them into one-size-fits-most vehicles. If your kid is especially young (short) it might not be possible to go this route. Some of them are tested for pretty tough abuse too, and suspension models are available if your kid likes to hot-rod around on local dirt trails.
You may very well end up with a 20"-wheeled bike that your kid doesn't outgrow, but gets bored with after a few years, and then *you* can start riding it instead.
Used bikes are also an extremely good value-for-dollar option. If you definitely want to get a kid-sized bike for your kid, then check around to see if you have a local bike co-op. These are usually filled to brimming with kids bikes at affordable prices, and you may find that having a relationship with the co-op is valuable unto itself.
Found a 7 speed 20 inch Giant at a garage sale for $20 this past saturday. It just needed a cleanup, new derailleur guard, new bottle cage (he thinks its cool), and a tune up. He ended up with a great bike that he likes for about $35! Thanks for everyone's help!