I'm looking for a real analysis book that covers measure theory and I've been recommended Folland's or Royden's books, but their price is quite high and I was wondering if any of the books below would serve as a cheaper substitute.
Theory of Functions of Real Variables by Lawrence M. Graves;
Real Variables with Basic Metric Space Topology by Robert B Ash;
Theory of Functions of a Real Variable by I.P. Natanson;
Real Analysis by Gabriel Klambauer;
Nonstandard Analysis by Alain M. Robert;
Foundations of Analysis by David F. Belding and Kevin J. Mitchell;
Foundations of Mathematical Analysis by Richard Johnsonbaugh and W. E. Pfaffenberger;
Mathematical Analysis by Tom M. Apostol;
Elementary Real and Complex Analysis by Georgi E. Shilov;
Foundations of Modern Analysis by Avner Friedman;
Real Analysis by Norman B. Haaser;
Introductory Real Analysis by A. N. Kolmogorov;
Introduction to Analysis by Maxwell Rosenlicht.