When buying a bicycle, whether for a child or for yourself, you should run through the following checklist:
Decide how much you want to pay and what you expect for your money. Visit as many bicycle shops as you can, and try to get an idea of what is available. Compare prices and types of bike. How often are you likely to use the bicycle? If you or your child is just about to take up cycling for the first time ever, it may be better to borrow a suitable bike, until you can see how much you enjoy cycling.
There is a range of bicycle types available. You will have some idea of whether the bike would be used only on the road, for off the road purposes (such as trail riding) or a combination of both. The type of cycling to be done will determine the type of bike that you should choose. Again, visit bicycle shops and ask about which type of bike would be best for the cycling that you or you child intend to do. Remember that self-assembly packed bicycles may require time and some technical expertise to build them.
Once you have decided which type of bicycle you would like, consider whether you would like a new or second hand machine.
A good second hand bike might be bought for the same price as a less sophisticated new bicycle. If you are unsure as to what to look for in a good second-hand bike, take someone with you who does know.
While it may be tempting to choose a bicycle for a child that he or she may be able to "grow into", it is vital to select a bicycle of a suitable frame size. This should be chosen with the child present, so that child size can be matched against the size of the frame. The ball or toes of a child cyclist's foot should be able to touch the ground while the child is sitting in the saddle at its lowest setting. A bicycle saddle and its handlebars have scope for adjustment, so the seat may be raised as the child grows.
For an adult cyclist, the correct frame size and saddle heights are such that the adult's tiptoes should touch the ground when the adult is in the saddle. Alternatively, the correct height may be measured by the adult's leg being nearly straight when the heel is on the pedal.
Once you have your bicycle, there are ways to make sure that, if it is stolen, it can be easily identified. You can mark a code or ID number on it. Make a note of this. If the bike is left outside, then you should use a padlock and chain to keep it locked up.