Some thoughts
Different people take different approaches. Here are some things to consider. Basically, you are asking two questions here:
1. Should I play rated or unrated?
2. If I get comps, how should I consider them from a bookeeping perspective?
The general consensus is that you should maintain your anonymity at all costs. It used to be possible to do this and still get comps, but nowadays, in most places, that is very difficult. So there is a trade-off between playing BJ anonymously, and getting comps for BJ play. At most places, a low roller is better off taking the comps IMHO, but it pays to educate yourself on a few things before you make a final decision. Namely, how liberal is the place on giving out comps, and what is their bet threshold before they start to worry about your action? If they will give you the type of comps you need / would otherwise pay for, and your bets are well below their pain threshold, then you might be better off getting a players card. HOWEVER, you also need to consider your likely future action. If you envision the possibility that you might be playing at much higher levels in the future, then this could change your equation.
Another option is to play BJ anonymously, and to get comps through rated VP play. Just make sure that you don't play rated VP and anonymous BJ on the same trip.
Also, remember that you don't need more than one free room per trip (unless you be rollin' wit a bangin posse - sorry, couldn't resist). If your destination has alot of casinos and you will be going there fairly often, then find one with decent rules at their BJ game, terrible pen, and willingness to give you a couple free weekend nights for 2-4 hours of play at your bet level. Play a break-even spread game there to pay for the room, and make your money elsewhere. Or you could do the same thing using VP at a place that has a great VP selection but no playable BJ games. The key here is to minimize the cost of your room, not to make a profit directly.
As far as accounting, there are two main approaches. You could count the comps as added income, or as a reduction of your costs. Most people count free stuff (food, room, etc) as a reduction of their costs, especially if they would have paid for it anyway. In other words, that free combo rain parka / car trunk organizer / beach toy set isn't really reducing your costs since you wouldn't have paid more than 12 cents for it in the first place.
The other approach is to count comps as additional income. This is more common with cash, or with something that you really would have bought anyway (like decent clothes from the casino shop). If it isn't cash, I record the value at the price that I would have paid for the item, not the sticker price. For example, I once got some comp points and discovered that the casino gift shop had half litre bottles of good scotch, which I would otherwise readily buy from a liquor store. Those bottles don't reduce my BJ expenses, and they are worth the price that I otherwise would have paid the liquor store, so I recorded them as additional income.
