There is a lot to unpackage in your OP.
I would like to "support" more of my friends in the coming year but also like a good deal.
Pretty certain this is going to rub a lot of people the wrong way. If you want to go the capitalist route, shop at a bigbox store if you need/want to find the best deal. It costs more to do business locally - that is just a fact. Local places can't depend on massive volumes. But they provide jobs, more of your money stays in the community, they volunteer/donate to your community, will probably save you money in the long run because they know you and your need (not always, there are always exceptions)
What kind of deals do you give or expect when "working" with friends?
Are you frustrated with friends & family asking you to do things for free?
If you are going to do business with friends you need to be very clear on if you are an asker or a guesser, and which one the person you are seeking to do business with. I think if we all understood this, we'd all be more successful at having our needs met and our relationships preserved:
http://www.theatlantic.com/national/archive/2010/05/askers-vs-guessers/340891/
My friend ownes a flower shop. For Mother's Day I said my budget was X and could she make me two bouquets within that limit? I got 2 beautiful bouquets & I gave her some business. Sure my X was more than 2 large grocery store bouquet because I didn't want to be cheap, but I still think I got great value.
I have another relative. They are a professional. They will Volounter to fix your fence & multiple other manual labour things. They are generous. But don't ask them to provide their professional services for free. I think that's fair.
I think photographers & artists are often asked to work for free. Can you donate to this? "It's great exposure."
What about lawyer, accountant, vet, doctor, advice?
Restaurant owners must get their friends always wanting a free meal deal. It could get frustrating.
Your flower store example is a good way to do it. You didn't go in and say: "I want the best deal you can give me and this is exactly what I want" You allowed your friend to use their expertise, knowledge of what you would like, knowledge of what was in their inventory and what needed to be used and gave her a set price point. This is great.
Your second example makes total sense too, they should be compensated if something is work related. Now you can always suggest a barter or something, if you think they would be open for it, but it is work for them. They may enjoy the opportunity to get out and do manual type things and if they are willing to help out on things like that, awesome!
Telling anyone with a skill that they make a living from that you are giving them "Great Exposure" is one of the most insulting things you can do. Great way to tank your business deal AND your relationship.
As with the restaurant, there is no such thing as a free lunch. A physical business has overhead, wages, and a multitude of other expenses to cover. A Photographer, a painter, everyone has supplies and overhead that must be covered, time and money invested in education and so on. They also need to make a living wage so they can continue to offer their service.
How I usually approach things, is quick advice is free. If it is going to take up my time, or resources, or supplies, I am going to charge for it - and you should expect to pay a fair price. Now I'm flexible, and more than happy to discuss alternative forms of payment or barter or whatnot. But it shouldn't ever be a given that you will get an amazing deal. Those tend to cost in the long run in one way or another.
Really, it is all about how you ask. It never hurts to offer a barter, or say you have x amount available, or things like that. If you assume you should get a good deal because you are a friend, or act like you are doing them a great big favor, then no, that's a crappy move and you should be shopping at a big box store if lowest price is your biggest concern.
We have a carefully cultivated network of friends who all have skills and experiences we can call on, and who can call on us. It's more of a skills share sort of thing, and with our group it works great. But knowing that Asking versus Guessing personality bit is HUGE to making it work.