Tcx has some good budget options if i remember correctly.

Theres also an ongoing topic abt boots u could read abt.

Rain wise, if ur not wearing over the shoe rain proof pants, water is gonna seep in n ull still be wet

Those Forma on LSH clearance are very good deal. But very limited on sizing.

Another issue with waterproof boots is, if they somehow get wet, it takes them a long time to dry out unless you have an air dryer for them. Dont use a hairdryer like I did.... completely wrecked the waterproof liner when I overheated them.
TCX has some budget line up and sometimes on sale for around 300. Unfortunately they are not sold as "waterproof". You could go to Hodaka Motoworld @ PJCC and check it out.

You could also go over to Serdang Motorcycle and check out thier budget branded Benkia range. They should be around the 300 range also.
Also, proper riding boots are supposed to be stiff for the needed protection. Get as high cut as you can find comfortable wearing.