Here in Almería, it costs around 1,500 euros a year to feed a horse plus another 500 euros for vet, blacksmith, insurance etc. This price does not include things like tack or installations. The financial costs are about the same depending on whether the horse is for pleasure, competition or therapy. Tack can be fairly cheap, depending on your needs (I ride bareback). The installations? How much do you want to spend?
Much depends on where you live as to the price of feed. I found that in the Cadiz area alfalfa sells for around one euro a bail, here in Almería it is around six euros a bail and in Barcelona it can cost anything up to fifteen.
The largest cost comes in time spent. The amount of time depends on the type of installations you have. If the horses are outside and free then there is considerably less work involved than if they are in stalls. Stalls need daily mucking and the horses have to be taken out and exercised plus clean water must be available at all times. There is no day off when it comes to animal care, no holidays; no Sundays. Then you have the training and care of the horses depending on the type of discipline they participate in. For competition, a tremendous amount of practice hours are required, the same goes for therapy horses since, even though it is not as physically demanding, they must still be prepared for every eventuality. They also need free recreational time. The job of a therapy horse is usually very boring: standing for long periods, walking around in circles, sometimes for hours and all sorts of strange exercises besides, so it is vital that therapy horses have a good work-out or run before sessions so that they are not bored and impatient.
When people come to ride once a week, they never consider the amount of work that has gone in to keep the horse in condition to ride, regardless of the discipline. If a horse gets colic, is in foal or founders, you may have to spend days and nights caring for them and still continue with your daily routine.
Horses and centres have to have insurance and to pass inspections. If you board your horse at a stable then there is the DIY system, where a place is provided for a fee, and all of the care of the horse is your responsibility, the usual boarding arrangement is that your horse is bedded and fed for a fee and you are responsible for its exercise. If the horse is to be trained or exercised it is for an added fee. The best system is where a horse may go in and out at its desire and a daily turn out or exercise is not mandatory but this takes lots of space.
Owning a horse is a luxury but one well worth the investment if you can afford it. Riding lessons or just plain horse-rental are both good alternatives but can also be very costly and, it goes without saying that the horses will have been ridden by numerous people of all different abilities sometimes leading to unmanageable or naughty animals.