Any idea of where to find baby things/items at reasonable & affordable price in Paris, France?

I will be visiting Paris, France next month for 3days and intend to take advantage of bargains on all baby items(clothing, feeding, complete travel system, toys, bath item, sleeping accessories etc). I do not know a lot of place in Paris and will appreciate information (web address, shop/store location, open market etc) on where to look. Though I intend to visit the district area where the OPERA is located and will be arriving in Paris via the Charles de Gaulle (airport).
Second Q: What bus ticket (prefer to travel by bus so I can see the beauty of the places around me) do you feel is suitable for my 3 days visit?

We have got most of our baby stuff from MONOPRIX. It’s a chain of stores, there are between 1-7 in each area of Paris. They have baby clothes, toys, games, all kinds of equipment, the prices are about as low as you can get for new stuff. Below is the link to the English language site for their store on Avenue des Champs Elysees.
Follow essonne’s advice for transport, and happy shopping.

Elizabeth gives Robin baby clothes

Baby Cupcake Pink Layette Set $25.00 4 piece set cupcake print tee matching hat bib has embroidered cupcakes pink panties cotton / polyester…

New Girls Boutique POODLE IN PARIS Clothing Outfit Set This outfit is outstanding. It can be worn as a dress alone or a two piece outfit.   Made of 100% cotton. This outfit is feminine and precious.  The dress has buttons down the back and a sash to tie in the back for a perfect fit. The print will be loved by all girls.  Ruffled trimmed with accent prints for a sweet finishing touch.  The pants have an elastic waist for easy fit.  This is sure …

Baby Short Sleeve Long Johns With Fifi in Paris Applique, 100% Cotton Knit / FR Treated, Lt. Pink Ooh, la la! Keep your little one comfy in these adorable baby long johns with fifi in paris applique by Kings ‘n Queens! Made from 100% Flame Retardant Treated flat knit Turkish cotton, its features include an easy to wear button down front, with soft and stylish appliqué on chest, cozy wrist and ankle cuffs, button front closure starts at crotch seam and goes down on both legs so you can pull on…

Sophias Style Boutique Infant Toddler Little Girls Paris Dress 12M-6X $30.00 A darling boutique dress for your infant, toddler or little girl from Sophias Style. This long sleeved dress features a black top with zebra stripes around the cuffs and waist. A pink flower also sits on the waist. The bottom is 3 tiers with a Paris Diva design on them….