Free and Cheap Things to Do in Seattle
Seattle's natural beauty and mild weather make it a fairly easy city to enjoy without dropping a ton of cash. Here are some of Seattle's local attractions that cost under $5 per person. (See also: 40 Most Useful Travel Sites That Can Save You a Fortune)
Seattle Museums offer free days on the first Thursday of every month for the general public (some of the museums also have free to seniors the first Friday of every month and free to families on the first Saturday of every month). At the Seattle Asian Art Museum, tickets for adults are only $5 on a normal day. Other local treasures that are expensive on a normal day but free on the first Thursday of every month include the Wing Luke Asian Museum, the Frye, and the University of Washington Burke Museum.
Speaking of dead celebrities, you can also visit the Jimi Hendrix memorial in Renton, just 20 miles south of Seattle.
Seattle has a wealth of public parks, but it really depends on what your needs are. You can play tennis in a variety of outdoor courts, which is great when tennis clubs are few and far between (but not so great when dealing with our 9,000 days of rain per year or whatever). Some great beaches can be found at Golden Gardens and Alki. We also have a large number of off-leash dog parks, should you need somewhere to let your pooch run free.
My favorite place in all of Seattle is the Arboretum, which is maintained by the University of Washington. It's open year-round, and is completely free to the public. (Also, it has great parking that rarely fills up.)
Seattlites are fairly proud of their highly-educated population (we beat Minneapolis in 2005 for the title of Most Literate City in the US, but those buggers keep taking the number 1 spot), so it's no surprise that we would build a huge central library that you can easily lose your children in (we will return them to you). We also have a huge number of used book stores, which can be fun to browse. Also, if you are looking for fellow nerds, you can head to the Science Fiction Museum (see above). Linux fans can walk past any of the dozens of Microsoft campuses and scream obscenities. (Technically, this is free, but Microsoft does ask for a donation of a part of your soul).
In spite of our hornrim glasses and pocket protectors, Seattlites are a fairly fit bunch. You might enjoy seeing the city on foot on a variety of walking tours (I like the International District, next to the stadiums, best). If you prefer two wheels to two feet, you can get a decent backyard view of Seattle by taking the Burke Gilman Trail from Ballard to Kenmore, on your bike (you can also walk, rollerblade, jog, or whatever suits your fancy).
Downhill mountain biking trails can be found under the I-5 Colonnade, if you have the desire to hurdle yourself across a crazy downhill course but don't have the vehicle necessary to get you out of the city. If you have your own set of discs, free frisbee golf can be enjoyed at the Lakewood Park Disc Golf Course. Being something of a disc golf newbie, I can also attest that Lakewood has a pleasant share of wild fruit, from apples to blackberries, growing around the course. The UW Rec Sports Center rents out canoes for $7.50 an hour, which is good and cheap with split between a couple people. You can row around the Arboretum, or even under the 520 freeway.
If exerting yourself isn't what you had in mind, it's worth noting that you can see the Mariners lose to any team in the league for as little as $6 per person (OK, OK, I know that's more than $5, AND you'll have to prevent yourself from buying the IchiRoll, the beer, or the chocolate-covered strawberries).
Obvious Stuff (but without the added cost)
If you're not from Europe or Asia, you'll probably be as thrilled as I am with Pike Place Market, Seattle's public market since 1907. I personally just enjoy walking around and gawking at the gorgeous flowers and produce and views of the water, since everything is a touch pricey (farmer's market prices). Kids also get a kick out of reading the names on the market's floor tiles, where you can find some pretty funny, intriguing, and sentimental dedications and names (the tiles were purchased as a part of a fundraising campaign by people who wanted to help rebuild the market, which regularly falls into disrepair, in the 1980s). The most famous site at the market is, of course, the fish-throwing guys.
It costs a lot to take the elevator to the top of the Space Needle, but I personally just enjoy walking around it and looking up. The Smith Tower offers a great view of downtown, but costs $7.50 per adult (still cheaper than the $16 that the Space Needle charges).
You might have noticed that Seattle has an awful lot of water, something that the Army Core of Engineers took advantage of when they built the Hiram M. Chittenden Locks. The locks are built between the Puget Sound (salt water) and our local lakes, Lake Union and Lake Washington. It's fun to watch boats come and go using the locks, and kids are especially enchanted with the fish ladder (please do not ask me why).
The cheapest food to be had in Seattle is at the international eateries sprinkled throughout the International District (formerly known as Chinatown) and the U-District (the neighborhood that surrounds the University of Washington). Vietnamese food is exceptionally affordable, but we have some decent taco wagons throughout the region as well. Also keep an eye out for happy hour specials at more upscale establishments or smaller bars.