I love Santa Monica and want to take my two young nieces (unfortunately in summer) but would like something less expensive that 200-300$ a night. The IH hostel is a possibility. Are there other places within walking distance of the 3rd St Promanade that I can consider? I know of the Carmel and California. Any others that won't break this aunt's bank? I don't want to stay where I will have to drive nor places unsafe to walk after dark.
The Santa Monica Hostel is well located and very safe. Children are welcome. Less costly motels would require a car. Metro Expo Line train will be open this summer close by takes you to downtown LA with connections to Hollywood.
I would NOT recommend bringing minor children to a hostel (and in fact many hostels don't allow minors). Having young kids sleep in bunk beds with strangers might make them feel uncomfortable and expose them to unsavoury characters or age-inappropriate behaviour.
Santa Monica is an awesome place to visit, but is definitely a bit pricey. Finding a hotel within that price range will not be easy. Have you considered looking on Airbnb.com? I noticed there are some apartments/condos available within your budget, and within walking distance to the beach. Here is one example:
The prices could vary depending on when you are planning the trip, and many of them are more expensive on the weekends. Also, be aware that when you search, the prices that show up are before fees and taxes. It's advisable to read the reviews and house rules to make sure the place will work for you.
I have had amazing Airbnb stays and find them to be more homey and unique than staying in a hotel room, and many times more affordable.
Good luck in your search and happy travels.