Straight to the tour works best. The fewer clicks between the "entry" page and the join page, the better. You can easily lose half your traffic on the first page.

Including the price weeds out some freeloaders. Just be cautious not to weed out too many that your CTR suffers and they require you to pay more per click. Usually not a problem, but it happens sometimes.

Best way to weed out freeloaders is to mercilessly tighten the campaign with negative keywords. "Free" being the first word to add to the neg-list.