It is not difficult to buy washing machine parts; however, it may be a little more difficult to pull that machine down and find out exactly what part is broken. If you are a true handyman, then this may not be anything to worry about, but for those who are not used to anything mechanical then it could pose a problem. The best thing to do is to get that repairman in to do the job and tell you what is needed.
You might be wondering if it is really worthwhile buying online as there is the freight to consider. But don't forget that your bricks and mortar stores also have to pay freight on the parts they get - and they then pass that cost on to you, as well as their other overheads. By buying parts online you can often get steep discounts as online stores do not have to pay staff or rent for a shop front. And often they will give you free freight if the cost of your purchase is over a certain amount.