A small business owner main preoccupation is to keep his business alive. So you are coming with a product that you are selling without showing or demonstrating or proving a tangible return of investment for that client.
Basically they will be paying a certain amount of money to you without the business owner realizing what kind of benefit he will get. I mean come on, would you buy your own service if you were a business owner, would you spend $1000 or $2000 on links and not knowing what kind of new business/clients these links will be bringing you. I don't think so.
So I think the issue is not that business owners don't understand, the main problem is that you are not selling them or bringing them any value on the table. if you can prove them that from their investment that they would be making, they can get a certain amount of client and that each client ( also you should know the monetary figure, ie for a dentist each new patient brings $1000, so if your links can bring him three or four additional clients a month, it is a no-brainer for him to pay you) and profit they might be interested and you'd be able to build a win-win relationship with that business which can bring you even more clients through referrals. But if you are blindly going to any kind of business and saying that they don't understand and blaming them for it, this is not going to work unfortunately.
In this forum, you can find a lot of experienced marketers that run agencies and have a pool of clients that they already work with. So they already have relationships with clients and businesses, what you can do is had them your expertise since they are looking for this kind of work to be done for their clients. I suggest to start with this. to some extent, Fiverr can work too, but since it starts with five dollars I think your target audience doesn't hang on there much.
Now to get to the next level which means that you will be selling directly to clients, you will need to understand the concept of value and value offering and include it in your proposal. Not simply focusing on technicalities such as links and the quality of links and blah blah blah, this is not going to convince anyone to buy from you. not even the biggest companies that have unlimited budgets. It's not because they don't have money, it is because you are not proving to them that they will benefit from what you're offering. As simple as that.
