If two people come up for the weekend, how much do you spend on food?

My parents are really picky eaters when they come up to visit me. Usually I can do my 4 person family's groceries for about $250 per week, so I figure when my parents come up, it will be an extra $100 for the weekend.

It isn't. They only drink particular things, all of which need to be bought specially for them. They don't eat the foods we do, so I have to buy their preferred cereals and things. I went to Costco and dinner for Friday night alone was $95 plus tax!!! I bought pork schnitzel ($48), a cake ($20), their drinks ($12), and a salad ($15). Then for lunch the next day they wanted these lamb things my mom saw the last time they were at Costco. I felt it was really expensive but because they don't visit often, I bought it. It was $45. Did they want the salad leftover from the day before? No, they wanted this bean salad thing ($13). Oh and then they wanted this potato soup ($17) and asparagus ($8). So now my total is up to $178 for two meals.

I suggested chicken, rice and veggies for dinner Saturday night, but they decided they wanted this chicken thing from Costco instead. I said I already had chicken and all the ingredients ready and my mom and dad insisted so I said fine. Oh, did they want EITHER of the left over salads or veggies? No. So the chicken was $33, the NEW salad was $8, then they wanted Brussels sprouts ($10). I'm at $229. Add in the $12 carrot cakes and I'm now at $241.

This is in addition to the orange juice I had to buy (they had one glass), the assorted Cokes/diet Cokes, root beers, etc, the pancake mix because they wanted pancakes on Saturday, the 18 pack of eggs I had to buy (but then they decided they wanted to go out for breakfast on Sunday, which was $125 for the 6 of us), the various chips and other snacks...

Their visit added on another at least $400 to our grocery bill. It has been unpleasant beyond belief any time they come to visit us because they are so darn picky. It's not that we're hurting for money here, but it's just excessive. Everyone loves my cooking but my mom (she's a "take it out of the box and pop it in the oven" type) believes it's much easier to just throw stuff in the oven.

Am I just being cheap?

Edit: my parents don't have a Costco and they believe it's cheaper. I told them it's cheaper and easier for me to just make the food. Now they say that they prefer the Costco food because of the taste.