I understand how frustrating it can be to work under budget. I have been there.
Here is what I think:
1. Indeed you can use blogs to help promote your products but can you update all your blogs in time? Because you need to constantly update your blog with content to make it standout. What do you think if the blog you read only have 2-3 posts and is outdated?
2. Can you put similar products under one domain? Then you can save your cost.
3. Can you just focus on few of your niches and drop other niches? Because I am afraid you will lose focus if you need to promote too many products in one time.
Hope these helps.
