Looking for advice on PR & Giveaways and how to keep our blog "real"

We've been blogging for a little over a year now and are starting to get some notice from PR firms. We've been offered some products and a giveaway promotion. We would love to have more traffic for our blog and maybe someday make a few bucks, but don't want to lose the fun of blogging. Also, how do others keep their blogs real without seeming like a big advertisement? Thanks for your input :)