I'm looking to purchase mini speakers that I can plug into the head
phone jack of an MP3 player or Disc Man so I can have an external
sound source. Obviously, they would need to be batery operated. Do
these types of small speakers exist, and if so where can I buy them?

Hello thumper1964-ga,

Thank you for your question.


My search returned the following results for speakers for your Disc
Man or MP3 player. They are battery operated or passive operation.


Sony Passive Portable Speakers
Model: SRS-P7 
Price: $9.99

“Add these speakers to your Walkman or PC for great sound. The
speakers join together for easy carrying and, at this price, you can't
go wrong.”

Speaker Type: 2" full-range bass reflex
 
Audio Inputs: Stereo mini plug
 
Power Requirements: Passive operation, no battery required
 
Product Height: 4-1/8"
 
Product Width: 2-7/8"
 
Product Depth: 2-5/8"

Source: Best Buy
http://www.bestbuy.com/detail.asp?e=11087532


You may purchase them at the SonyStyle website as well.

“Sony's SRS-P7 Passive Portable Speaker System join together for
portability and is lightweight and easy to carry. The SRS-P7 features
bass reflex duct design for powerful bass, stereo mini plug input and
requires no batteries or external power source. Just plug it into your
portable audio product and start enjoying your
music.”http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en/-/USD/SY_DisplayProductInformation-Start?ProductSKU=SRSP7



PANASONIC (RP-SP28 ) 1.6 Watt Mini Speaker System

Built-in 0.8w x 2 amplifier
2-way speaker units
Uses 4 AA batteries
Availability: In Stock - Same Day Shipping! *on orders placed before
Noon (PST), excluding weekends and holidays
RP-SP28
http://store.yahoo.com/kb-electronics/rp-sp28.html


The above speakers are also available at Buy.com for $14.99

Features Product Description - Panasonic RP SP28 - speaker 
Product Type - Speaker 
Dimensions (WxDxH) - 3 in x 2.5 in x 3.9 in 
Weight - 0.6 lbs 
Localization - English 
Speaker Type - Active 
Max (RMS) Output Power - 1.6 Watt 
Input Impedance - 4 Ohm 
Audio Amplifier - Integrated 
Connectivity Technology - Cable 
Speaker System Details - 2 x right/left channel speaker - 0.8 Watt - 4
Ohm
Battery - 4 x battery AA type
http://www.buy.com/retail/electronics/product.asp?sku=90102762&loc=111


The Panasonic speakers are on sale for $12.19 at SpectraVox
http://store.yahoo.com/spectravox/rpsp28.html

ShoppingMatrix Price: $12.42
http://store.yahoo.com/lpcs1/rp-sp28.html


Here is another option from Sony although it is a bit more expensive.

SONY ( SRS-T55 ) 2 Watt Folding Personal Travel Speakers
http://store.yahoo.com/kb-electronics/srs-t55.html

Folds for travel
1w x 2 amplifier
Neodymium magnet
Uses 4 AA batteries or optional AC power supply
100Hz–20kHz
8 7/8" x 3 3/8" x 2 1/4"
Retail: $49.95
http://store5.yimg.com/I/kb-electronics_1738_77788620


Search Criteria:

Mini speakers
Portable mini speakers
Battery operated portable mini speakers


I hope the above speakers meet your needs.  But if not, just make a
Request for Clarification, and let me know how else I can be of
service before rating my answer and closing the question.

Best Regards,
Bobbie7-ga

I have used the Panasonic speakers mentioned by Bobbie7. They are very
nice, and are an excellent bargain. They are small enough that I can
carry my portable CD player plus the speakers, and fit the entire
package into my purse. Despite their small size, they have a good,
clear sound quality.