as salaamu alaykum wa rahmatullah,
First of all I ask that Allah (swt) make things easy for you and all the other married people out there in agreeing on these issues because they can lead to a lot of problems... I think disagreements on financial matters are one of the leading causes of divorce, both among Muslims and non...
I would suggest that you take a look at you and your husband's financial situation *as a whole* and see how much money you really have coming in, what it's being spent on etc. That way you will get a better idea of what it is reasonable to expect from your husband in terms of money for your self (or 'allowance' though I really don't like that term -- how about calling it 'guilt free spending money' instead
) For example, if you guys have a total of $1000 a month coming in to cover ALL of your expenses including groceries, etc, then wanting a $200 spending allowance is not really practical. BUT, if you have $3000 coming in, then maybe it is or a different amount.
Whatever your 'allowance' is, you can also supplement that with your own money (from your savings before marriage, your parents, etc). Now doing this, especially with money from your family, can be sort of a delicate thing for a number of reasons... as Br. Hard2Hit mentioned it may cause some gheera/ego issues in the husband, OR the opposite may occur as Sr. Fozia mentioned, and the husband may adopt an attitude of 'Well since you already have money, why should I spend on you?'
My big suggestion here would be to always talk about and consider that money as a *gift* from your family and not like 'help'. Since it was a gift for you, you can decide how/when to use that money, and as a gift it won't really be considered an affront to your husband's ability to provide. I would also suggest that you use that money for occassional 'big ticket' items that you and your husband cannot afford on your own ex. a really expensive camera, a plane ticket to visit them, etc. That way it is not affecting your budget or your day to day spending habits, but you are still enjoying it. As a 'gift' these things can be accepted with no hard feelings (as opposed to, for example, using that money to buy groceries or shoes or something where it can lead the husband to feeling inadequate or that what he is able to provide is not good enough for you, etc)
If it's a matter of your husband's parents controlling the money coming in I would suggest that you two make a serious budget where you set aside money for the things that are most important to you and make sure that you are receiving that, and not worry too much about the rest. I have a friend who's husband basically is not honest with her about how much money is coming in and how much he is giving to his parents etc. It was a long term problem and finally she decided on this: Every month they have a set, agreed upon amount that they must have for the house/groceries/daily expenses, the childrens immediate expenses, savings for the childrens future, and for herself/personal allowance. Since he is good about giving that set amount to these areas she has decided to be content and let him use the rest of the money the way he wants. I know it can be hard, but just think about what your priorities are and try to get those established first. Insha'Allah with some communication and calculations you guys will come to a good solution
may Allah grant us halal rizq and baraka in our spending,