Paying a vinyl installator to remove vinyl stickers from your car could become expensive if there are many of them and he charges by the hour.
The most cost effective way of removing vinyl stickers from your car is to do it yourself. To do this, use any household hairdryer and warm up the vinyl to loosen the adhesive. Start with an edge and slowly start to peel the vinyl away. If you feel any resistance from the adhesive reheat the area until the vinyl peels away easily. Go slowly and gently to avoid any damage to the car's paint.
Once finished, remove any adhesive residue using an adhesive remover or isopropyl.