>I am wondering what it could be the
>expenses to open such business>
>Abdul :D

Expenses for any retail shop will likely include these:

rent
utilities
advertising
payroll
supplies (everything from toilet paper to calculator paper)
racking
POS (point of sale cash register etc)
counters/tables
cooler (for the flowers)
office machines
office furniture
professional fees (accountant; lawyer)
signage
permits
taxes

As you can see, it is a very costly endeavor.
Write up your business plan so you know exactly what you will need and if you can afford to start with a brick and mortar shop.

Good luck with your plans!