for their hospitality and financial support through the Peter B. Kenen fellowship. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research. NBER working papers are circulated for discussion and comment purposes. They have not been peerreviewed or been subject to the review by the NBER Board of Directors that accompanies official NBER publications.

I study the positive relationship between prices of tradable goods and per-capita income. I develop a highly tractable general equilibrium model of international trade with heterogeneous firms and nonhomothetic consumer preferences that positively links prices of tradables to consumer income. Guided by the model's testable prediction, I estimate the elasticity of price with respect to per-capita income from a unique dataset that I construct, which features prices of 245 identical goods sold in 29 European, Asian, and North American markets via the Internet by Spain's second largest apparel manufacture-Mango. I find that doubling a destination's per-capita income results in an 18% increase in the price of identical items sold there. Per-capita income differences account for a third, while shipping cost differences can explain up to a third of the crosscountry price variations of identical items purchased via the Internet by consumers who do not take advantage of quantity discounts. The price elasticity estimates compare favorably to estimates that I obtain from a standard dataset that features prices across retail locations around the world, suggesting that variable markups play a key role in accounting for observed crosscountry differences in prices of tradables.

This paper presents novel evidence of price discrimination, using prices of identical goods in 28 countries. I explain the observed phenomenon via non-homothetic preferences, in a model of trade with product differentiation and firm productivity heterogeneity. The model brings theory and data closer along a key dimension: it generates positively related prices of tradables and income, while preserving exporter behavior and trade flows of existing frameworks. It further captures observations that richer countries buy more per product and consume more diverse bundles. Quantitatively, the model suggests that variable markups account for 80% of the positive price-income relationship across 123 countries. JEL codes: E31, F12, L11* Ina Simonovska, Department of Economics, University of California -Davis, 1 Shields Avenue, Davis, CA 95616. 612-703-2265. inasimonovska@ucdavis.edu. I am grateful to Timothy J. Kehoe and Fabrizio Perri for their continued guidance and encouragement throughout this project. I also thank

Quantitative results from a large class of structural gravity models of international trade depend critically on the elasticity of trade with respect to trade frictions. We develop a new simulated method of moments estimator to estimate this elasticity from disaggregate price and trade-flow data and we use it within Eaton and Kortum's (2002) Ricardian model. We apply our estimator to disaggregate price and trade-flow data for 123 countries in the year 2004. Our method yields a trade elasticity of roughly four, nearly fifty percent lower than Eaton and Kortum's (2002) approach. This difference doubles the welfare gains from international trade.

We argue that the welfare gains from trade in new models with micro-level margins exceed those in frameworks without these margins. Theoretically, we show that for fixed trade elasticity, different models predict identical trade flows, but different patterns of micro-level price variation. Thus, given data on trade flows and micro-level prices, different models have different implied trade elasticities and welfare gains. Empirically, models with extensive or variable mark-up margins yield significantly larger welfare gains. The results are robust to incorporating into the estimation moment conditions that use trade-flow and tariff data, which imply a common trade elasticity across models.