As an American who has spent the last year living in Australia, and 3 months traveling through SE Asia prior, money was definitely an obstacle along the way- but never a complete roadblock. Before that I studied abroad in Europe in undergrad - so I was especially on a tight budget then. Here are 5 tips on my insights to traveling solo and on the cheap -
1. Stay in hostels / Couchsurf / Airbnb
Stay with Locals and Make Travel Friends - Couchsurfing is NOT as sketchy as it sounds. Even as a solo female traveler you can safely stay on a fellow travelers couch for free and learn heaps more about the city than you would in a fancy hotel paying extortionate amounts.
If you're still a bit hesitant, hostels are cheap alternatives to hotels. You're surrounded by like-minded travelers (often on similar budgets), and some are actually quite accommodating. Check out the reviews before you book on Hostels Worldwide - Online Hostel Bookings, Ratings and Reviews and Hostels, Hotels & Youth Hostels at hostelbookers
And lastly, my new favorite, Airbnb! A cheap alternative to hotels, Airbnb allows you to stay in other people's homes (and usually meet the owner's as well - providing lots of insight and local advice on your current city). I've recently stayed at Airbnbs in Tasmania as well as London and couldn't be more satisfied with each experience!
2. Be a backpacker
There is a nomadic lifestyle associated with simply using a carry-on size backpack while traveling, in lieu of a rolly suitcase. You'll skip the airlines charges for checked luggage, you'll learn to prioritize when packing, and you'll skip the impulsive travel buys simply because you don't have the room in your bag.
3. Pack a water filter (and reusable bottle)
When traveling through Asia, my friends and I saved heaps by simply packing a water filter. This way we were able to refill our water bottle wherever, and not have the worry of getting sick in the case that it was contaminated water. These days there are even water bottles with filters attached within them. However, I used a simple life straw and never once got sick. Amazon.com : LifeStraw Personal Water Filter
4. Set up your networks prior to leaving
In this day and age of social networking, you're bound to know someone (or someone who knows someone) in the destination(s) you're headed. Reach out to friends and let them know your travel plans. Most likely they'll give you a connection in the area, and if not, they might just be able to give you some tricks of the trade for traveling solo there. There's nothing better than meeting a new friend in a new destination, and having them show you around. You get the perspective of a local but still have the feeling of an explorer.
Be sure to check out local groups on Facebook, Couchsurfing events & groups, or even just websites like Hommily, a social network specifically made for travelers.
5. Eat the street food!
Pad Thai off a cart anywhere and everywhere in Thailand is usually around $1 and equivalent in size to that of 3 dinners. And, as if that wasn't good enough, it's DELICIOUS. While you should always have your guard up regarding the cleanliness of street food, if you dismiss it altogether, you will truly be missing out on a good chunk of the best part of traveling - experiencing other cultures. My personal recommendation - just stick to the most popular street carts. If there is a line, it's legit (specifically if the line is made up of locals)!
5A. Find alternate forms of transportation (Less safe, more money-saving)
Depending on the mode of transportation, usually the cheaper the expense, the less safe the vehicle. I've ridden motorbikes in Thailand, electric bicycles in Myanmar, unstable TukTuks in Cambodia, highly unregulated buses in Northern Vietnam, non-airconditioned overnight trains in Southern Vietnam, uncomfortably packed vans in Laos, etc. If you can dream it, (and you have good coordination) you can most likely cheaply ride it.