Looking for some budget bookshelf speaker advice

Hi am looking to put together a second system for my cellar gym. The room is about 5m square with a low ceiling. I already have an old sub to go with the system any thoughts on what speakers would be good to get looking for something nice and cheap am tempted by the wharfedale diamond 9.0s for 50 quid also seen some interesting stuff around the hundred pound mark but would prefer to spend a little less second hand would be fine too but wouldn't know what to go for. Thanks for any suggestions