There is no property tax in Dubai, so are there no other costs?

No tax does not mean no costs. You still pay a 4% DLD transfer fee, on a resale roughly 2% agency commission plus 5% VAT on services (on off-plan and direct-from-developer purchases the developer covers our fee, so you pay us nothing), annual service charges (often AED 10-30 per sq ft), mortgage fees, a 5% housing fee via your DEWA bill, plus maintenance and insurance. One-off transaction costs typically run 7-8% of the price.