Before buying any service online, you need to consider the following
1)Your budget - you will see many companies offering huge amounts of resources at low costs but most of the time you will not get the quality of service, you may find slow speeds, when you need support they take days to reply or they are not 100% above board with their licencing, quite often offer you annual plans for around £50 - £100 for a VPS server or web hosting plans at around £10 a year but within a few weeks/months you will receive an email (if you are lucky) to advise they are no longer offering services and you must seek a new provider. The cheapest option is not always the best, sometimes spending a little more will give you peace of mind.
2)Location - Decide the location that the bulk of your service users/customers will be coming from if you are running an online store that only ships to the united kingdom hosting your website in the USA or Canada would not be the best idea, you would be best suited to the united kingdom as if you have issues you are in the same timezone as the company to assist in getting things resolved although companies advertise 24x/ support always best to be in the same timezone if possible.
3)Before putting your main website or service on a provider, buy a small package first to test the waters, sometimes explain you will be moving your main websites over in the future and will be trying out the services, sometimes you will be offering a trial or discounted rate during your testing period
4)Check that their licences on software services such as cPanel or their billing system (eg WHMCS) are legitimate by using the online licence validation pages on the software companies websites if the companies are not using legitimate software if a company is not using legitimate software they are not taking their business seriously and will soon disappear along with your money and data.