This could be quite outing and long so I'll try to keep it brief. MILs car is old, broken down and pretty much unusable. She needs it for work (who have been completely unsympathetic but that's another story). I have a car which she has been borrowing "just for work" (fully insured for this) but its becoming more and more often and being used outside of work and leaving me stuck nearly everyday - I'm on maternity so dont need the car as much but Im tied down to when she's busy and she makes me feel guilty for saying no/offers to drop me off at said place I am going and pick me up 
DH doesnt drive but is nearing his test and hoping to buy a secondhand car.
I go back to work in a month so she will have to stop using my car then. She cries to DH that she cannot afford a new car, can't afford this and that for her kids etc and is pushing him into getting a finance car solely in his name and they can share it and she will give him half the money each month (she says she has a bad credit rating so can't get the car in her name). DH doesnt want to as more than likely he will be left paying the finance off and I'm sure this is illegal (?) and not fair to keep pushing onto him at all. Instead, he has offered to lend her £600 of his savings for a new car, which she could get an ideal car for her and her 2 kids. My first car I bought off Facebook and it was great so I sent her a link to a few cars. She said she'd rather have a finance, newer car and that night badgered DH on the phone and also cried saying she had no money so he gave her £50. I thought this would've been for an emergency, food, bills etc?
The next day I went shopping with her and she spent over £60 on cushions, curtains, home accesories etc that she doesnt need just wants as she is updating her living room. It's made me so mad that she guilt tripped DH to offering her money but can spend and spend and spend. Not to mention she's gone on a last minute holiday to Portugal.
DH said he isnt going to get the car out on finance but with the way its going it looks like she will push him into it as soon she will have no use of my car and is still refusing the offer of getting one secondhand.
She is normally lovely but it's made me so angry that she is using DH like this (and to a certain extent me, she lied about giving her friend a lift in my car and said she was working).