Don't let the clothes wear you, you should always be the one wearing the clothes. Ill fitting garments are bad style. Either too large or too small- both ends of the spectrum produce very bad style results.
I observed a good number of people at the Newport Jazz Festival yesterday whose clothing was wearing them not the other way around. Some folks were just poured into skimpy, ill fitting summer frocks while others in an attempt to be comfortable in the outdoor venue were just looking like they had endless yards of fabric draped over and around them.
Your clothes should always skim your body, neither too tight nor too loose. You can always buy an inexpensive item of clothing as long as it fits and can carry accessories. Low-end garments or second hand does not mean you cannot do some clever alterations. You can wear almost anything you like new or old as long as you are careful and you wear it and it does not wear you.