If you can offer them something that they need (price, quantity or other), then you may be considered for their business. Otherwise, they may have other companies that they will consider. Getting your hat in the ring basically means: getting involved being involved being a part of something be considered for involvement

It's an expression: it is kind of a challenge to you to supply him with a price quote or something so that your organization is in contention for their purchase order. It goes back to old sporting events, where people interested in taking up a challenge or betting on the outcome might throw their hats into a "ring" (a boxing ring, something like a corral or fenced-in area). For example, in the US presidential primary elections, we have presidential candidates who "throw their hats into the ring" by announcing their candidacy. A costly, protracted election campaign is usually what follows.