This is a toughie. It probably feels like a no win situation, cuz one of you has to give in, and whichever one does, that person is going to have to deal with some very difficult feelings. On the other hand, the "winner" doesn't win either, because what he or she also gets is a spouse who is dealing with some very difficult feelings that can grow into a great divide.
I would give it some time, but I also think you need to find a way to discuss it, and especially the feeling side of it, so you the burden of this doesn't grow and fester.
You don't want to nag him for a baby, but you don't want to force him to have one either.
His concerns for your welfare and very kind, and it's good to be married to someone who wants you to keep your options open, so you aren't forced into the workforce unless you want to be. But at this point, I think a vasectomy is a rather final decision, whereas your decision to be a homemaker might change once your child is in school.
If you do not have other children, perhaps there are ways to share your love with other children, as well as your own. You could look at volunteering, (once your child is in school, so you don't have to worry about child-care), at the library as a reader, in the school system, at hospitals, and/or social service agencies. Finances being what they are, the non-profit sector is in dire need of assistance, and volunteers who really love people are in high demand. You may find that this opens up a whole new world for you, one in which you are able to make a difference in the lives of people who are desperate to interact with people who care about them.
On the other hand, you might want to really look at your husband's fears. And perhaps he ought to as well. Is he worried about the finances? As a truck driver, he is facing the reality of the deisel fuel prices, and it's scary out there. I honestly don't know how truckers and trucking companies are surviving this mess. Maybe he doesn't want child #2 because he's afraid of making ends meet right now, with only one child. And in this day where people are out buying huge TV's, paying high cable bills, cell phone bills, and then losing their homes over it, it's good to hear someone wanting to be cautious on the expense side in order to be able to care for his family. He may be feeling a bit out of control of his life, and making this decision would give him one thing he can control. Still, a vasectomy is a drastic solution and should be decided by the two of you. (My husband had one)
The economy is not good right now, and the future is very uncertain. I think I would hear him out, but be sure he knows how you feel and how much you really would like to have another child if it were affordable. (It's no fun to have a child, and then not be able to provide for him or her.) Perhaps you could decide not to have one for now, and to revisit the idea in 6 months, and maybe a year.
We don't know what the future holds, and American budgets are being pushed to the max right now. Given the fact that you are on opposite sides of the issue, I believe the best thing you can do for each other is to listen, and to wait. Sometimes when you wait, another option becomes crystal clear. For instance, What about foster care? It isn't an easy job, and you would be having to love and nurture children who come to you with all manner of uncertainties and sorrow because they've been plucked from unhealthy homes -- but maybe this is an opportunity you should consider. It's having more children, without the same financial burden. (?)
Above all, keep talking to each other, and keep listening. Don't let this turn into an opportunity to put barriers up that grow and destroy your marriage. I am assuming that you wouldn't want more children if you didn't love their father, and that he doesn't want more children because he loves you and wants to be able to support you and your son. There's love on both sides, so hang on to that. Every marriage has its roadblocks, and we have to find ways to surmount them, not just survive them.
I have friends who, for whatever reason, were never were able to conceive, and in the end, later in life, they were able to adopt a baby boy. (After a few times getting close and having the potential baby whisked from their grasps) . . .They are a wonderful family. They love each other. They dote on their son in some ways, but he doesn't lack discipline or responsibility. They are simply very active in everything he does. Having just one child, and being so very thankful for him has meant that they are very active in scouting, they go to all his sporting events, they camp together, they do as much as possible with their son, specifically because they love him and don't have to decide between doing something with one child or with the other. They gladly give up stuff they might want to do, in order to raise their son to be a healthy and mature adult. (he's 14 now). In that sense, they are a model family -- because so often today, you just don't see families who are so tuned in to each other as family members. Their togetherness grew out of heartache, because they really wanted children and couldn't conceive. But they worked through it, and around it, and while they couldn't afford to adopt more than the one, they are so very excited to have a child to love and nurture and to be blessed to participate in his development.
You guys will get through this. It's not a dead end in the road, it's just a really huge pothole, and you need to raise your eyes from the massive ditch in the way; give yourselves a broader perspective, so you see the good as well as the struggle, and then work together on how to get beyond it.