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, roughly 2% agency commission plus 5% VAT on services, annual service charges (often AED 10-30 per sq ft), mortgage fees, and a 5% housing fee via your DEWA bill. Add maintenance and insurance. One-off transaction costs typically run 7-8% of the price.