I didn't read ahead so I don't know if I am repeating anything.
I have family in the floral industry and I worked with them for several years. We were suppliers to flower shops and the company is still doing very well. I was the NC sales rep. The biggies are FTD and Teleflora.
IF you go through one of your local florists and they call a local florist in the town where you need the flowers delivered, you will incur a wiring fee and delivery fee with your purchase. Those charges alone can sometimes run up to $20 per transaction.
That said, I do send flowers often and I have a certain florist in each town I work with specifically. By using them directly, you can avoid the wiring fees but you still can't avoid the taxes and delivery fees.
Some places have a minimum order for delivery so keep that in mind. I've never spent less than $60 when I want to send something relatively small and this includes the taxes and fees.
Flowers are beautiful and also expensive. You cannot expect to get a quality delivery for cheap. You will get what you pay for unless you end up with a florist that is not ethical and they take good money and send an arrangement that is worth 1/2 the price.
I think you might need to rethink your budget or be ready to add the special fees to your budget as it is.
I have not used the 1800 flowers or Pro flowers. I've heard pros and cons about both. Just remember if you go with someone like this, they are the middleman and you might be able to save money if you work directly with a well known florist in the area.
One thing to do is when someone receives flowers from you and they call to thank you and so on... ask for a picture of what was delivered so you know what you got for the money you spent.
Another option is... the local grocer/Super Target, etc. Do you know someone who can go to your local grocer flower shop and buy flowers for you and deliver them? I buy flowers from my grocers florist that are beautiful and good quality. A very nice assorted bunch of flowers (no vase) runs $20 and up and last over a week. You can also choose per stem as well and each stem runs about $2.00 and up. I've seen stems that were $15 each for something more exotic.
I hope this helps you with some ideas on how to get some flowers to your mom in the most economical way.