You consider a few things when you join a marathon. Think of the entrance fee or registration fee, travel expenses, running gear or equipments, and the training. The total cost will depend on your marathon, and its location. The marathon organizers determine the amount athletes will pay. If you join local or low key marathons, the fee would be about $50-$60. That is fairly little. Major or famous marathon events have a more demanding fee than the local events. In fact, some marathon events require their participants to come up with at least $300.00 for the assigned charity for them before they can gain entry to the particular event.
The location of the chosen marathon event affects the cost as well. Of course, it will mean a lot whether you do a local or international marathon event. With international marathon events you will have to book 2 flights for back and forth. The farther, the more expensive you will pay. If you join a local marathon event, you pay much less for the transportation.
Regardless of the entrance fee, kind of marathon event (major or minor), location of marathon (national or international), preparing for marathon is not much. You have running gears and equipments to buy. Of course, you want to buy the proper outfit but that does not mean expensive running clothes. You probably even have a pair of decent running gears. Even so, running gears are not expensive. The equipments too are fairly affordable. The most bought running equipment is watch with GPRS. That too depends on your taste and preferences with watches. These sort of stuff depend on your aesthetic sensibilities. It can be cheap. It can also be expensive as you like.
Finally, you have the marathon training. It is a need to consider this matter. You just do not join a marathon without a proper training. Marathon training schedule or marathon programs are not expensive. You can buy it at less than $100.00. The training runs for different length of time. There are training for 12 weeks, and 16 weeks. Some do training for several months in advance of the Big Race especially the beginners. Whatever level you are as an athlete, you can fully give your confidence to your trainer or coach to train you well and good. Marathon training schedule have programs fit for beginner, intermediate, and advanced athletes. It is up to you to determine in which category you do belong.