bonkers

Sorry if this question has been asked a million times already i have done a search and coudnt come up with anything .I am a British citizen born and bred there i am planning on moving home to the uk with my 3 children oldest was born in britian so has english passport like myself .Younger 2 were born in usa ,my problem is this i can not afford to get the younger ones both sets of passports usa and english ,so do they really need a english passport before going home ,if me and my oldest are travelling on uk passports and my youngest 2 travel on usa ones will i have problems when i arrive in heathrow with them .thankyou in advance for any help .
im a very confused and homesick mum right now .