I bet there will be a ton of window AC units for less than $50 or $75 that would work for you if you can't find any dual hose units (just make sure they are split like the diagram i posted, some use indoor air to help cool the outside radiator and waste co2)
Good luck
Buy electriQ Easy-Fit DIY 9000 BTU WiFi Smart A++ Inverter Wall Split Air Conditioner with 4.5m Pipe Kit eIQ-9WMINV from Appliances Direct - the UK's leading online appliance specialist
www.appliancesdirect.co.uk
This one would work right ?