It might seem funny to talk about 'shoestring tools' but there are various things which will make 'living on a shoestring' easier.
The first tool is a kitchen big enough to cook in, when we are travelling I always try and stay somewhere where we can cook as it just saves so much money. The second tool I think is essential is a means to get around, whether you live close enough to walk to everything you need or use a bicycle, scooter or motorcycle being able to get to jumbles sales, charity shops and to collect items from Freecycle will save you a lot of money. The third tool which won't cost much but will help a lot is a library card. Membership of the library will give you access to books, lots of reference materials, the internet and maybe CDs and DVDs to watch. Some libraries in the USA even loan out membership cards to local museums and art galleries and we took advantage of this when we lived there. The final tool in this basic armoury is an attitude of contentment, look around you and think of all you have rather than envying others or wishing your situation were different.
On the next rung up for tools would come some more items you might like to acquire such as indoor drying racks for clothes drying in the Winter and a slow cooker for easy meals on busy days. Some basic tools for gardening such as a trowel and spade would also come in handy if you want to grow a few herbs and vegetables. In this category wold come a good, frugal cookbook and possibly some other books about budgeting and frugal living. I keep mine to give me inspiration and encouragement when mine is flagging. I also think a washing machine saves a lot of money at the laundrette !
In the third tier of items to acquire are things which will allow you to do jobs which otherwise you would have to pay for, such as chimney cleaning rods or car repair equipment. Barber's clippers have saved us a lot of money in haircuts over the years as have various items from jumble sales such as a pressure cooker and a bread maker. I also like to have a printer at home as it saves me dashing out to print things and then buying other stuff on the way.
I'm sure that there are lots of other things which I have forgotten so please add to the list in comments, what do you find most useful on your 'shoestring' journey ?