Let's say your character has a minor titan bloodline. At level 1? You get jack. You pay jack. You're a completely ordinary character. You play as normal. You level up as normal. However, when you hit level 4, you get +2 to your Jump skill, and you still level up normally, gaining Power Attack at level 8 and so on.
Here's the cost. Bloodline levels. Depending on how strong your bloodline is, somewhere along the way, you need to take a bloodline level. This is similar, but not identical, to level adjustment. For our minor titan bloodline, we have to take only one bloodline level, and we have to take it by level 12 or suffer some penalties.
A bloodline level gives no hit points, not even from constitution, offers no skill points, not even from race or intelligence, and offers no BAB, saves, or class features. However, it still counts as a level for purposes of effects based on character level, maximum skill ranks, and it advances all class features based strictly on class level. For example, it increases Wizard's caster level, but not spell progression. It boosts paladins' smite damage and mount abilities, but not their smites/day.
If you have multiple classes with abilities based strictly on class level, then your bloodline level applies to all of them. One bloodline level can advance Monk unarmed damage, Paladin smite damage, and Sorcerer caster level (but not spell progression) all at the same time.
Now, if you were to take a medium bloodline, you'd get your jump bonus at level 2, your power attack at level 4, and have to take a bloodline level at level 6, and again at level 12. You gain benefits later that the minor bloodline doesn't grant at all. A major bloodline requires bloodline levels at levels 3, 6, and 12 and grants even more benefits.
You only choose ONE strength. You have a minor bloodline, a medium bloodline, or a strong bloodline. whichever you choose, find that column on the appropriate bloodline to see what you get. You're only looking at one column. The costs are the same regardless of which bloodline you choose. It's one bloodline level for minor, two for medium, three for strong, at the same rate.