trying SPD’s can be expensive, so I’d suggest cheap shimano pedals (505’s lasted 3 years) 520’s can be had for around £25.
Shoes are the awkward bit. they are stiffer than flats so can rub and be uncomfortable, force your foot to be in positions you may not normally put them in, and like all shoes, fit is important. I’d be tempted to get something cheap from ebay, see how you like it then invest when you know what you want.
I have some Scott shoes, which took ages to break in but are ace now (though heavily vented so definately summer shoes and some nikes that were given to me by a friend which are a bit loose but look like smart shoes(ish)