Dead easy to change and dirt cheap to buy, personally I would say DIY it every time and save wating money on paying a dealer to do it (or not) because if my own experience is anything to go by the dealers rarely do change them themselves even though they charge for them as part of the so called "service"
Thanks for the reply Alexank. I can vouch for it being a very easy change but I can also say beware of filters that claim they fit. I ordered Purolator C38208 - although it said it fitted it did not so I returned it. (Amazon)
This one did fit: Genuine OEM 97133-D3200 Cabin Air Filter / 97133D3200 for Hyundai Tucson 15-20 Veloster Kona Venue, Kia Sportage 17-20 Soul 20- / Replaces J9H79AK000 97133J9000 K2C79AC000