Combinatorics: Theory and Applications by V. Krishnamurthy.
This is an undergraduate text. Comprehensive and clear. If you live in India, there is an additional benefit: it can be yours for Rs. 275 only (I bought it on flipkart for Rs. 215 recently). It covers Polya Theory, Schur Functions, Matching Theory, Inversion Techniques, Ramsey Theory and Designs. It has a large collection of examples and problems.