With increasing availability of technology, there are now lots of solar panel installers. The following are not definite, but give you an idea of approaches.
Pay, Install & Maintain
The apparently simplest approach is to have the equipment installed for a fee and then the technicians leave and you have your own installation which is all yours. These solar panel installers will probably be able to offer further service and maintenance in an on-going relationship.
Long Term Feed in Tariffs
There are companies which offer long term schemes whereby you don't buy the equipment up front but instead allow them to fit the panels and then take advantage of what are known as feed in tariffs. You get cheap eletricity and possibly an make money. You get to have a green conscience and possibly cheaper living. You do have to usually sign-up for a long time, such as 25 years, which can be off-putting. These types of solar panel installers can offer an alternative perhaps for those who don't want the up-front costs but would still like to get involved.