I would recommend increasing the price of that gas station. It looks like a good model, and I'm sure it took a while to create. Everyone thinks that lower prices will translate to higher sales volume and more money, but that is almost never really the case. If you make a sale for $5, you could have probably made that same sale for $10 and had double the profit. I wouldn't go less than $10 for that type of model, but that's only my opinion.
Also, just a word of caution: If you are going to sell the gas station model as a 3d printable asset, it is important that you include dimensions of the model in your description and tell potential buyers what the minimum thickness tolerance of the pieces are. As you know, 3d printing requires certain specifications that most people are looking for when they purchase models for printing. If you do not include these specific details in your description, you will probably not get as many sales for that model. This is especially true for complex models like that gas station. At first glance, someone might think it is not a printable model and seems more suited for game assets or props.
Your work looks interesting, and I wish you very much success!