Hmmm, I've seen silent auctions of individual donated high-price items (hard-to-get- tickets to a sporting event, autographed sports memorabilia, a new technological gadget (an iwatch, etc). But in each case, the key for a silent auction item is that you have to be able to get it for less than market value so that you can make $$ on it.
Alternatively, I've seen people put together fun baskets for raffle - the total value of the stuff in the basket is typically around $50. This is the category that I would put a star wars basket like you describe in. I can't imagine a basket of board games, water bottles, and legos going for over $250 regardless of how much you put in it.
If you are supposed to do a basket for auction, I would suggest thinking of 1 high-priced item that you could buy, then ask local businesses for filler items.
For example, you could do a sports/fitness basket and you buy the newest fitbit (make sure you tuck the receipt in the box in case the buyer needs to return it for any reason), but then to increase the value, ask local sports teams to donate memorabilia and ask the local sporting goods stores to donate gift cards, ask a local gym for a complimentary 1-month membership, etc.
Or an adult reader's basket, and buy the newest Kindle Voyage to put in it with an Amazon gift card, 2 bottles of wine, and ask local bookstores to donate gift cards.
Or a gaming basket with a pair of virtual reality gaming goggles but before you buy them at Best Buy, explain what you are doing and in return for purchasing at their store, ask Best Buy for some donations to go with them (gift cards or accessories).
Or an adventure basket with a Go Pro, and ask the store where you buy if they will donate accessories, etc, and ask a local trampoline park (or something similar) to donate a few tickets for admission.
You have to have some way to make the value of the basket more than what you paid for it otherwise I agree, it doesn't make sense.
Sometimes silent auctions will have a minimum set for the item, and if the bids don't equal at least that amount, the seller can return the item to get the cash back to donate. But this is rare, and you'd have to talk to the parent group in advance if this is what you want to do.