Refusing a dress from a co-worker

My co-worker is now considered senior citizen, (60yrs. old). Suddenly she tapped me and told me she bought a dress online that might fit my size. And she wanted me to check it out for the next day and that she will bring it. Well, i know that she wanted me to buy it, but that's not how I buy my dresses. What i usually do is go to the mall and do canvass until i get the perfect dress that i wanted. I really invest on my dresses contrary to my usual outfit inside the office that may be the reason why she's thinking that i will buy the dress instantly because it's not expensive and i look like i dont buy expensive ones. That online shop that she is talking about offers cheaper prices but the quality is just

There's no harm in checking out the dress. Maybe you'll like it. You can always say that you're not interested later.