I ride a Giant SCR as my commuter and light tourer (i.e. rear panniers only). It’s perfect for the task.
Sure, it’s not as sturdy as a Galaxy or similar, but it’s a well enough made alloy frame with carbon fork that looks (apart from the freaky bar position 😉 ), just like midlifecrashes’ bike above. It’s well made and, given that the model MLC and I have retails at £500-ish, must be available s/h somewhere for something like your budget.
At 5’7″, I the SCR I ride is a “small” in Giant’s frame sizes. Because it’s so compact (measuring 46.5 cm), it’s hard to compare against a normal (i.e. horizontal top tubed) frame). I suspect it’s somewhere equivalent to a 52cm (I can ride up to abouyt 54cm, depending on TT length).