Buy it at a pet supply or farm supply store. 

Usually I end up going with a big box store on flooring and appliances, and the GC gets everything else.

A big box store can provide exact $ numbers for your material list. 

@Padma Mody you're going to find your best prices at the big box stores like HD (Home Depot) or Lowe's.

Yes the REO inventory is very thin and competition for those is high, as you've seen.I'd recommend getting some practice talking to owners/sellers directly; you'll have to do it sooner or later anyway, and the sooner the better IMO.For example, try "driving for dollars" which means driving (or biking or walking) around a neighborhood near you and calling on For Rent signs to ask if the owner might want to sell instead, or talking to people in the neighborhood about any vacant/derelict houses you see.You might also attend a local real estate investor group such as RIREIG in RI or Black Diamond in Worcestor/Waltham.

For such a small house, I would think a shed would be a nice feature to store stuff in order to not crowd the house.  

You will find out plungers aren't at every store...  

If what you buy is not near a school, not near transportation lines, not near a hospital, not near a park, not near stores ask yourself why would someone want to buy your house especially why would they want to make an offer on it right away.

One of my first private lenders, very unassuming older gentleman working at thrift store, loaned me 20,000 on a project, later asked if I needed more, another 30,000, few month later another 50,000 over a two year period was up to 180,000. 

Although rules vary store by store, the Home Depot, I frequent limits use of their truck to people who purchase items in store.