"If you have to ask, you probably can't afford it."
Seriously though, if you have to contact a salesperson, it's likely that the product is a "reorganize-the-entire-budget-to-pay-for-this product" type of service. Ergo, if that isn't appealing to you, you aren't the target market, and therefore a waste of time to them. This assumes a "smart" approach as nostromo mentions, of course.
I'll add the caveat that I see several "idiot" approaches to this simply because the "talk to our sales rep" approach is the default in many industries, particularly B2B. You can often hear it expressed as "If we publish our prices, our competitors will know them too!". In my industry - insurance - I've seen 6 figure sales consultants involved in week long sales processes that make us $200 in revenue a year. That's not "smart" at all.
There isn't a 'right' approach, but it depends entirely on the product being sold and the target market whose needs are being addressed.