I have used Rugbystore and Lovells and they are both very good. I actually ended up visiting Lovells to exchange a shirt and their staff were very helpful so having met some of the people behind their operation I wouldn't hesitate to recommend them. Rugbystore now have a flat rate shipping charge which is much better than their previous system but it is a little more expensive than Lovells.
I have also used Newitts.com who are very good on postage costs and also accept Paypal. I have bookmarked Eggcatcher but I haven't used them yet, if I do I'll put an update on here.
Regarding boots, always go for leather uppers (it will pay off in the long run), avoid anything "blade" style (my opinion only) and avoid over intricately moulded soles (they will break!). In general, Forwards use 8 stud boots but you might want to consider 6 studs as a Loose Forward depending on your role and the general playing conditions in Latvia.
