For which of you, intending to build a tower, does not sit down first and count the cost, whether he may have enough to finish it; lest perhaps, after he has laid the foundation and is not able to finish, all those seeing begin to mock him, saying, This man began to build and was not able to finish. Luke 14:28-30
To me this verse has a couple of things it is stressing. First, if you want to buy something you need to consider what the cost will be. If you're building a house, you need to consider the cost and save up your down payment and get a loan. You need to plan ahead and get your financial house in order, before jumping into something without a plan (as so many have done nowadays – ending up in foreclosure). Considering the costs might sometimes mean not going through with a purchase. So carefully consider the costs, and whether something is worth it.
This verse in context is also speaking about considering the cost of being a disciple of Christ. We have to be ready to give up everything we have for Christ, and remember that everything we have here on earth is His. We need to be ready to lay down our lives, our possessions and everything else – and realize that anything we have except Christ has no real worth. In this passage Jesus says it plain and simple:
In the same way, any of you who does not give up everything he has cannot be my disciple. Luke 14:33
All of us have something in our lives that needs to be given up for Christ lest it become an object of our desire. For some its money. For others it might be their possessions or an unhealthy relationship. Any number of things can become your focus, and whatever it is, if you aren't focused on Christ it can become an unhealthy thing.
Consider the costs of becoming a follower of Christ and think about where your focus is. I know from personal experience that when you put your focus on Him, you'll be much happier in the end no matter what happens in your financial and personal life.